As Robert said, there are plenty of legit providers who were never listed here or who once were and are gone. Plenty of innocent reasons to be delisted, most common being the provider’s choice.
BUUUuuuT, it’s always possible someone realized she had a good reputation here and is now delisted, and started a scam using her name and photos. Less likely is that she made a pivot from legit provider to some sort of scammer.
How much do you remember about her old profile and how long has it been gone? If you were satisfied that her reputation here was totally solid and she hasn’t been gone long, then she is probably fine. Is this ad you saw in the same place she advertised when she was listed?
Search engine her name and contact info from the ad you saw. (Each thing separately.) If you can find old ads from before she delisted with the same contact info that’s on the ad you see now, that’s a pretty good sign. If she has a verified, active SM that goes back to before delisting and mentions this tour to your city, that’s a good sign. If she has a currently active P411 that goes back to her time of being on here, then you’re probably golden like the shower.
At the end of the day you’re going to have to go with your gut and take your chances. There’s no reason to think that her being delisted from here proves she’s now dangerous.
You will be more likely to get better intel if you post this on the local board of her old home city and/or cities she toured often, if you can remember.
