I'd say that people over 40 have a better chance, via videotape, than younger people--because they have to have SOME older people--and those that apply constitute a smaller group; generally, because we older folk have too many responsiblities, jobs, kids, etc., to be able to travel away, for a month--and we DON'T go to Belly's Bar!
Also, because we older folk are more circumspect--in public--we might not show our interesting personalites, in a shopping mall, etc.
I think that, since they are making challenges harder, they want any older people to be MORE athletic, than they will allow younger people to be! For instance, Ryan Shoulders and Rob Cesternino were both couch potatoes, with not-so-good jobs--would they allow an older person of the same--um--abilities on?
And it's Bull that they DON'T like naked video--because they have SO many that DO get on! The advantage of naked video, is that it's going to be viewed by SOMEBODY!