It's entirely possible Though I've always got a refund in the end, generally how it works is they'll flatly refuse, then one of the regulars will say "well **** you then, if you want to see me here again you'll give me a credit", which they do, then everyone else gets one. They're not daft, better to get people back 4 times a year than to keep the money once. But that would obviously vary a lot from place to place.
There was a big hoo-ha last year, Brands Hatch got heavily snowed on just before a trackday and they "cleared" the track- or rather the racing line, 4 feet wide, and said it was safe to ride Salt and loose snow all over the place. Luckily they chickened out of that after a few people dropped the the words "suit" and "law"
+1 on the learning. just feel out the traction. build into it. and remove as much bodywork as possible prior to going out.Ride in the rain---you'll learn alot
and you dont have to have rain tires either
hell my brothers 1st trackday ever was when he was 15 years old on my old SV650 with pirelli slicks--and he moved up to intermediate in the afternoon!