You can never tell, the SSSSilliness is airline-dependent - sounds like she's "flagged" on UA at least.

The check-in agent may override the SSSS if you talk nicely, but it's completely discretionary so if you get a ***** having a bad day, you're out of luck.

You can insist on a same-sex screener and also a private screening. This is done in a separate area or room out of public view, if that's the issue. It may take a bit longer, the TSA would prefer you didn't go this route and may drag their feet over it. Be firm.