I've met an untold number of well known drummers.
And for the most part, I rarely have anything to really to ask, it's not like they don't know who they are, and with the net, you can look up interviews with said player to find answers to most common questions.
I've also been to a number of clinics where someone asked a really dumb question, and I don't want to that guy!
I remember being at a Tony Williams clinic, and someone asked him what does when the wing nut on hi-hat clutch comes loose, and Tony just looked sort of dumbfounded, and said "tighten it." Oye.....