I'll be visiting the TT for the second time this year and be back in August for the MGP for the third time so I'm probably a "new visitor".
Despite having been to loads of UGPs, Mid Antrims etc, I must admit the thing that pushed me over "the edge" and actually make my first trip was watching the Closer to the Edge in 3D in my local cinema. I thought the time trial nature (versus the wheel to wheel racing of the Irish races) wouldn't interest me as much, but I loved it.
I know people worry that "newbies" won't want to volunteer, but I did at the first possible opportunity and then roped my wife in too! Over two summers we've both "qualified" as marshals and completed the IMC and had a great time virtually everywhere we've turned up. Even at this year's TT I'm only there for 1.5 racedays but, if they'll have me, I'll bung on the orange bid and marshal for a day (I've even convinced my mate to join in).
As long as a % of all these newbies sign on (and keep coming back...) the races will survive - the trick for those who have been there for a while is to make them feel welcome and part of the team (and not moan about how it was much better when XXX did YYY...
) - which, in my experience is something that most current marshals do really well.