I've generally found that apart from air experience flights, unless you are prepared to lend a hand you aren't looked upon very favourably by other club users. If you're keen and go out of your way to help you will find you tend to get more flying and get on better with the instructors and other pilots. I've had a day when I've turned up, had an early flight and gone home and it doesn't go down well. I didn't do it again! If you're going to take it seriously then expect to muck in and spend the day, flying or not. Teamwork counts!
Cheers,
Sywell-Flyer