She's putting her bare foot on the fender - I see no problem with that. A quick wipe with some Ultimate Quik Detailer and a clean microfiber and you'd never know it happened. I also doubt she'd be spilling or splattering the nail polish all over the car either. Were that my car, I'd happily let her do what she's doing - and I'd likely observe from the driver's seat. Think about that one for a second.