No-deal Brexit on 31 October could make life "very difficult" for the UK music industry says the BPI.
The organisation, which represents UK record companies - including Warner, Sony and Universal - believes copyright laws might be "thrown in the air."
They say "chaos" could ensue for British artists touring in Europe too.
"Planning for a whole range of possibilities which we are not sure will ever materialise is extremely difficult," says the BPI's Ian Moss.
At the most basic level, Brexit raises concerns about the ability of musicians to tour overseas. And unless you're The Rolling Stones or Beyonce, touring teams don't come much bigger or work more often than orchestras.
Classical musicians agree no-deal could mean uncertainty over work permits, delays at European borders and complications with moving instruments across the continent.
"The nice and simple crossing at Calais, with 100 musicians and no obstacles," could instantly become a thing of the past by Halloween, says Mark Pemberton, director of the Association of British Orchestras.
Orchestral manoeuvres in the dark
"We've got orchestras that are going on tour in November who do not know what the work permit restrictions and extra costs are going to be in, say, France or Germany. In terms of their preparation, there are some very big unanswered questions."
Even if work permits are granted, he believes European concert halls may look elsewhere as "there's only so much they're prepared to spend on booking an orchestra".
"If we become more expensive [extra costs-wise] than a German or Italian orchestra then guess what? We're going to lose the work."
"The saving grace for us, ironically," he laughs sardonically, "is the is the weak pound, because we're all now cheaper! [performance fee-wise]"
Another obstacle touring musicians could face is having to pay for a permit, known as a carnet, for every instrument they take into Europe - to prove they are not trading them internationally.
Tales of musicians bringing back broken strings from the US and Japan, to satisfy officials they had not sold any of their equipment abroad, are already part of touring folklore.
Moss suggests carnets could also prompt bands to ship their merchandise, which is often made in Asia, directly to Europe to collect en route, rather than paying to bring it over the border.
May contain animal products
Believe it or not, some instruments taken into Europe by British musicians contain small amounts of "endangered species" like ivory and rosewood.
After Brexit these would need declaring, but the ABO claim they've been told key ports, including Dover, Calais and Holyhead, are not set up to inspect the necessary paperwork, meaning further delays or re-routed trips.
Pemberton thinks even if orchestras plan their diaries carefully, they could still end up scrapping whole days of work.
"Let's say you're a busy orchestra," he ponders, "with a concert in London on the Sunday, booked into a recording studio to do a film score on Monday and then you're off to Paris to perform. The recording session is now gone because you need Monday to guarantee you're going to be in Paris."
He suggests an "emergency fund" should be set up by the government during this "make or break" time.
"We're flagging up all the problems that they need to start thinking about. We're prepared to break even but if we lose money going on tours then that's not viable."
The BPI is petitioning the government "to ensure people can work and freely move abroad in the EEA (European Economic Area) area without visas for 90 days within any 180 day period, so they can tour and work abroad".
While they deal in people - aka recording artists - the BPI also deal in goods and services. Moss notes most of the physical products made for the UK music industry - CDs, vinyl, cassettes, etc - are manufactured within the EEA and that the plummeting pound had already pushed up costs by a "significant amount".
The Intellectual Property Office - the government body responsible for intellectual property rights - last year published guidance on copyright in no-deal situation.
A spokeswoman says UK copyright laws do not depend on membership of the EU.
However, Moss maintains copyright is a "central issue" and has been a real "concern" for BPI members in discussions with officials.
Before he became Prime Minister, Boris Johnson voiced his disapproval of the new EU copyright law, which made services like YouTube liable if users uploaded copyrighted material without permission. In a tweet, Johnson called the law "terrible for the internet" and said copyright was an area where the UK could "take back control".
His stance understandably gave the music industry cause for concern.
"We would not want to see anything that creates uncertainty and the government should not take this opportunity to start throwing copyright law up in the air and reconstructing it," says Moss.
"Our real concern, though, is through trade deals - particularly with the US. There's the potential for importing very unhelpful copyright legislation which they have in the US, where we don't get broadcast public performance rights [royalties for songs played on radio and TV]".
"So it's important to keep copyright stable whatever other chaos is going around."
No-deal Brexit is a very British concern, but it could pose problems for foreign musicians working in the UK, too.
Creative Scotland believes "working internationally" and attracting the best talent to Scotland is key to the development of homegrown talent "and the ability of artists to exchange ideas".
They do, however, note the UK's Creative Sector Tax Reliefs will not be affected by Brexit.
Last year musician and Womad festival co-founder Peter Gabriel criticised the UK government's approach to handling visas after a string of international acts were forced to pull out of the festival.
"It is alarming that our UK festival would now have real problems bringing artists into this country," he told The Guardian, claiming many "no longer want to come to the UK because of the difficulty, cost and delays with visas, along with the new fear that they will not be welcomed".
One year on, festival director Chris Smith tells the BBC there is "no indication of what will happen in a no-deal fantasy land".
"From an artist perspective, we will be back in a situation where EU-based artists simply won't want to commit to travelling to the UK.
"In the current climate who can blame them?"
Music industry representatives have been attending briefings with the Department for Digital, Culture, Media and Sport.
A DCMS spokesperson said: "Preparations for leaving the EU, under all circumstances, are now the priority of all government departments.
"We recognise the importance of mobility and the temporary movement of goods for major events, tours and productions, and we continue to engage closely with the music industry to ensure impacts are understood and plans in place for when we leave the EU."