I did visit a FBSM massage place  and the provider when got to know her confided in me their are hidden cameras. she did acrually show me where it is.  so my question is as hobbyist  what  precautions can one take if to patronize incall locations?   since then for most part out call has been the solution ..

When doing something that is illegal, I'm not sure if the legality of non-LE cameras is an issue. (LE can get court permission to install secret cameras but they can't install them in bathroom stalls, massage table views where nudity is expected, etc. without extra special permission ... if ever.)  
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So, if some non-LE entity is using cameras, the Q is what they subsequently do with the images. If they try to extort you, you go to LE and go after THEM for extortion. If they post pics to the internet, you go after them using the pertinent laws (non-consensual porn; revenge porn; etc.).  
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I HOPE that hidden cameras are more for security or for the massage place to give to LE in the event of a crime by a customer.  
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If you are only getting a legal FBSM and you think you are being illegally recorded, I am guessing that YOU can report it to LE and ask them to investigate. A search warrant and a ladder will answer that Q. Seizure of the recordings could open up a whole other can of worms!  
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I wonder if there is a polite way to ask them to turn off the cameras? "We're friends, right? I'm a good customer, right? I'm on your tapes from the lobby and reception area. Those are LEGAL. But I don't want you recording me nekkid in the room. Please turn off the cams while I'm in there or let me cover them up with towels. OK? [I would NOT add "Or I will call the cops on your illegal recording of nekkid people w/o their permission.]"  

The cameras are probably there to prevent the masseurs from ripping the parlor off. The parlor usually gets some cut of the masseurs proceeds. A masseur could easily say that a client just wanted a massage and didn't get a HE, or that the client only got a BJ etc. If they can see what the masseur does they can determine what she charged and what their cut should be. Also a masseur could "poach" customers by simply exchanging contact information with clients. I'm sure being watched cuts down on that behavior.

If you are hobbyist, chances are there are photos and camera shots of you everywhere and you're on a blacklist somewhere. You should already know this by now. More often than not, these providers know more about you before you even screen. They say the destroy the screening info but they don't. If you are a nobody, a regular joe, you have nothing to worry about. If you are a well known somebody then you have reason to pause.  

Also keep in mind, in New York State, one party surveillance in ones home or place of business is legal. This means they don't have to tell you or ask you for your permission to be filmed in their place or establishment.