I bet the creepy losers at the gym who sit and stare at the women in the hip hop dance class don't think they are creepy losers. But they really are. You're just sitting on that machine. You're not doing anything but ogling those women.
Also observed at the gym this evening:
A couple of ladies who could have used a really good sport bra. In fact, they both could have used any bra. Anything at all. Those tits are already saggy -- you don't want to be bouncing around with no support.
The best place to train your personal training client is definitely in the space a few feet from the drinking fountains and next to the entryway to the locker rooms. I can't imagine she'd feel uncomfortable or anything. And there's so much space for her to move freely. You're certainly not in anyone's way.