This sounds like this could be done right and be a new direction in bookselling, or it could be done wrong and be a business-killing waste of everyone's time and money.
In any event, you have to ask what's going to motivate the public to fork over their money. I'm sorry, but meeting a writer just isn't privilege enough to pay for, imo. Hell, many of us can't even sing or dance.
A book
event needs to be an event if it's going to support both bookstores and writers.
I agree with the tiered approach concept. Simple signings, at a foldaway desk, during regular shop hours, should not be special, paid events. I think they should be just part of the repertoire of promotions that bookstores and writers do.
Special events that are set-off spaces, or off regular hours, and may require reassigning staff, should be a pay-or-buy proposition, and they should be advertised widely and in sufficient advance. And they should always offer something more than just standing in line for a signature -- a wine reception/meet-n-greet; book readings; maybe a writers panel discussion of some sort. Event things. If they can showcase emerging/debut authors alongside more established authors, that would increase their value as well, imo.
Yeah, I can see a lot of ways this could be very good and a lot of ways it could be made of fail.