+1 for all of Rowan's points above, courtesy to the other riders and to the volunteers is something I always try and observe. The volunteers aren't getting paid for working and as to the food and drinks, taking more than you safely need is just irresponsible and wasteful. I seriously doubt most of the 50+ members are table raiders, those types creep me out anyway. My one peeve is the riders that want to make the low key charity or club ride, regardless of its length, into the Queen stage of the TdF. Bulling your way through riders in congested areas, especially the start of the events, is unsafe and rude. Plan your starting position if you are going out hard and fast, our big events stage the starts so that the fast, looking for a great Strava time riders, start first and can scoot up the road without the others getting pushed aside. A little courtesy and maturity goes a long way and makes a great day that much better for everyone.
If you haven't worked as a volunteer at a century or other event, you really should do so. Its is just paying the rest of the bicycling community back for the times you got to enjoy an event. Getting in on the organizing side of a big century is quite a challenge, and it is very satisfying to watch and hear the riders enjoyment during one you helped put together.
Bill