I have yet to personally see a single mentor acting the role. It wouldn't be the first time I find newbies in any Roulette, and it's me explaining the mechanics while the mentor is completely mute (I'm not a mentor, nor do I wish to be).

I think the problem with mentors is the big reward that SE added for them. Instead of wanting to become a mentor to help the community, people simply want to farm the mount. The moment you add such a reward, the point of being a mentor gets severely misplaced >_<