I don’t see how this warrants a negative review
The booking was agreed so a review can be written. If you don't like that rule for reviews then you're out of luck.
If the punter doesn't feel safe or feels that an escort is being indiscreet,having her pimp/boyfriend/brother/whatever standing around chatting to the neighbour next door then in my opinion he's fine to abandon the booking and leave a negative review. It was his experience, his review and his decision. You're free to ignore his review in the same way I might ignore a negative review for a cancellation by a well reviewed escort.
If you still think this shouldn't be a review then you can report it to Admin but I suspect he'll ignore you.