Personally, I think that the TCA is just trying to take advantage of the fact that they rent the fairgrounds for pretty much the whole week, so why not try to get some revenue coming in for the non-meet days? And maybe even entice some people to join TCA and stick around for the meet (not all hotel vendors are in TCA).
The impact on the hotel shows will probably be minimal, with the possible exception of the people that setup outdoors at the Wyndham. They are always at the mercy of the weather, and the idea of having indoor space and not having to pack up each afternoon and set up again the next morning might be enough to lure them to the Purple Hall. Unless the other hotel/firehall vendors are unhappy with their venues, I don't see many of them giving up their regular spots. I find hopping around York to the various shows kind of fun. I wish I had been there for the golden years where the bandits were more numerous.
This move has had a small impact on me and my traveling companion in that we usually arrive in York early Wednesday mornings, and this York we will be arriving on Tuesday to check out the activities and the new Purple Hall "bandit" show. And if we find it worthwhile, this may be our new itinerary going forward. And I think that is part of the goal -- get people to come earlier and stay longer. I applaud EDTCA for doing something to try and add value to the meet.
Andy