yes, questions about antiques, who else is in the house, if there is an alarm system, if there is a police station next door, if there is an expensive entertainment system in the building,are all possible red flags. A bit of common sense - if the caller wants to discuss things that are even more removed from what the treatment is about, you need to be careful. If they want to discuss things that make you feel uncomfortable, for whatever reason, don't let them make an appointment. If you met someone at the bus stop and they started asking about your antiques, who is normally home, if you have a safe behind a painting, common sense would be saying "don't invite them into the house" and it would probably be saying "maybe you should not get on the same bus with this person", you use the same level of common sense with callers. The red flags I mentioned before are mainly about people looking for extras without specifically asking about extras, but ANYTHING that common sense says is unusual should also be considered a possible red flag.
But some people are anti-antiques - eg Billy Bob Thorton has an antique phobia, can't be in a room with them, bigtime Holllywood movie star is not going to ring you up, but maybe his assistant could. I probably would consider someone asking about antiques as not the type of client I was interested in and someone else would get to massage Billy Bob Thorton.No single massage therapist can be the right massage therapist for all of the population, you're under no obligation to take appointments with every caller. It can be difficult at the start when finances can dictate the need to work on as many people as possible, but if you are uncomfortable about the client for any reason, they're probably going to pick it up anyway and not come back, either because you're not comfortable with them or they really were looking for something other thana massage, extras/antiques/whatever.
I have to admit I've always assumed people asking about who else is around and if there is a side entrance where they won't be seen
have alwyas been just looking for extras rather than scoping the place out for a robbery, whatever the reason, the result of not giving them an appointment means I will never find out for sure. If I did have a lot of antiques/safe behind the painting to be concerned about, I might be more aware of questioning along those lines.