Re: Physical contact vs. "no-touch" policy
I think Aikido and physical contact are understood to go hand in hand. After all, it is a martial art and we all sign waivers that cover injury occurred during potentially dangerous training, that would certainly seem to suggest benign innocent touch occurs as well.
The trick is to discern the level of appropriateness and the intention of the "toucher."
For adults, we can maturely deal with accidental "not-so-inocent" touches. For example, a female during Nikkyo or Sankyo on a male uke might place his hand on her chest, depending on the variation. While taking ukemi, he might slip and accidently brush against her breast. Adults can understand that is not the intention and was innocent.
For children, I think that as mentioned above, clear communication with parents is essential. The best solution, if size of dojo permits, is encouraging the parents to observe their children's classes so the parents can see what goes on and how everything fits together. The parents should be active in their children's activities anyway, whethor it is Aikido, sports, or internet use! Whatever is done however should be done in full view of other instructors, and ideally the student's parents. Private one-on-one with a child is just a bad idea.
"Predatory touchers" are a whole separate can of worms, and must be dealt with at least by the head instructor of the dojo after a victim approaches them about it. I doubt that there are any Senseis who would actively allow such abuses to continue once informed of it. If so, it not be a dojo that I would train at.
As far as males vs. females in society, I agree that society does indeed look at males differently, maybe even for legitimate reasons. I am a male school teacher by profession, and one day, one of my students, a 13-14 year old girl, tripped over, and was on her way down backfirst into an overhead projector on the ground. I moved in behind her, over the projector, and placed my arms under hers, catching her and stopping her fall. It took her about a few seconds to regain her footing. All I could think of was "Oh my god, this looks BAD!" Luckily nothing happened, but I think it goes to show that even innocent situations can "look" bad to someone unfamiliar with the context. There have been countless other times where students have stood or leaned over "too close" requiring me to move a few inches away.
If there is ever any doubt about the intention of a contact-situation, I think it must be dealt with directly, but allowing the "toucher" some degree of benefit of the doubt. Hostile or predatory intentions I think would be obvious when the incident is discussed with the toucher, over an innocent misunderstanding, or necessary touch.