I like my thigh-length PI cycling shorts, too, but I'm not crazy about the tan line. That would be my main motivation for getting shorter shorts. Ah, vanity.
I also wear tank tops for riding. I picked them up at Footlocker for $5 each. Can't beat that. They're long, loose, light cotton that dries quickly and are really comfortable to ride in. I do wear sports bras underneath. It would have to be really, really hot for me to ride in anything less.
I've got a couple of sleeveless jerseys, too, but they're short and I feel like my waistline is exposed when I ride in them. I'm not quite that much of an exhibitionist.
As for that woman's behavior, well, props to her obviously high self-esteem, but yeah, if she crashes, I pity her the road rash. Was it a "Woman in Red" kind of thing, where she wasn't aware that she was putting on that kind of display, or was she luxuriating in the attention that her hotness was drawing? Some women are just more exhibitionistic. (Is that a word?) Others are focused on the athleticism. I have to admit to flexing a bit more myself when my husband is around. He appreciates the view, and I appreciate his appreciation, you know?
As for the guy grabbing your butt while riding, did you really need a boost up a hill? I would have been shocked, too, believe me. I'm not experienced at all in group rides, though. I've never seen anyone, male or female, "boost" anyone like that. Maybe it was perfectly innocent.
Roxy
Getting in touch with my inner try-athlete.