Yes of course it is legal. Hotels generally let people booking a room pay on arrival but they don't have to. You need to check your booking conditions.
Hi this isn't a hotel room booking - it is an event 3 course sit down dinner for 150 people. most hotels will just take deposit which they have already and bal paid on day of event. they said its too complicated to pay on day
Seems a bit strange so alright. Doesn't leave any negotiation if something is not up to scratch. Has everyone going paid you ? I presume you are a club of some type and it's funded by a ce4ntral pot ?