I know it's not a real rule, but to have an idea about the "perceived age" of a Rendo character (at least in the eyes of the creator) you could simply look at the promo pictures. Almost all "adult" character do have a nude picture, while "underage" characters do not. For example, Aurelie and Tanith are clothed in their promos, so I would avoid to use them in hot situations.

Then maybe some vendors do not like nudity at all in their products, or some stores (like Daz) do not allow it.... but anyway if the rule fails it fails on the safe side.

Giorgio

giorgio_2004 here, ksabers on XBox Live, PSN  and everywhere else.