If a masseuse advertises using her real identity then a text or call from an unknown prospective client is unlikely to get a positive to a HE question, you could be her husband, friend, dad, anyone.
If her name is Wendy and she works in a TCM shop you know you are going to get wanked off anyway
A client asking during a massage when the lady is working home alone could be very frightening as, if she doesn't do HE, she may fear she is about to be sexually assaulted even if that is unlikely.
Unless you are prepared to play the long game with an unknown its not worth it just go to a reviewed provider.
Clues to no HE, keep underwear on, draped, doesn't do the glutes or abdomen, doesn't go above the knees, whacks the towel right into the gap between your thighs, all under the offer of a 'full body' massage lol.
So unless you get off on scaring ladies be a gentleman, play the long game and eventually reveal that yes you are a pervert who wants a HE!
Cues that a HE may be a possibility, she stays in the room and watches you get undressed, doesn't cover you with a towel, starts telling you about all the guys who ask for a HE, keeps touching your balls and cock accidentally, is really crap at massage and makes you think she must do HE or what's the point, apologises for rubbing your cock accidentally at which point you say oh that's OK I like it. Trouble is this hardly ever happens and you spend a small fortune finding out.