Understandably, events are only a successful as volunteers can make them.
Remember too, the attendees who push, pull or drag their MVs to such an event are also volunteers who have invested many thousands of dollars into their craft . It is not unreasonable to ask for defined details well in advance to facilitate planning time off work, arrangements for transportation etc.
Not everyone likes last minute surprises.
All too many events "want", with unreasonable expectations, and then wonder why they have limited or no response , or participation.
Flipping someone a can of fuel or a few bucks for gas is a kind gesture but it comes up far short of a participant's real costs.
We do this because we love to, not because we have to. The general public does not care, nor do they respect what goes into these events or who owns the vehicles...