Here are some observations from the EU side on the touring issue facing musicians

2/ The European Commission offered the UK a standard mobility clause in its draft legal text back in March last year that would cover musicians, sportspersons etc... It's on page 354 of the EU's opening text ahead of the negotiations

3/ Under a standard mobility clause, acc to one official, EU member states can ask for visas for certain people coming to carry out paid activity. However, there's a list of exemptions for people who don't need visas:

4/ This list includes those "travelling for the purpose of business deliberations..., sportspersons or artists [including musicians] performing an activity on an ad-hoc basis, journalists sent by the media of their country of residence, and intra-corporate trainees."

5/ In other words, under a standard mobility provision, musicians, journalists, sports people and business people who travel to discuss contracts etc do not need visas. Officials say this is the standard EU arrangement for third countries, eg the US.