So there is a private viewing massage place in a decent location that I am thinking to frequent. They clearly state they do not do offer FS on their site. I heard they provide happy ending by some of the staff.

To me, I like getting a massage by a white spinner which you do not normally find in normal massage places (mostly run by asians).

I clearly text and schedule saying I was a back massage when I reach out to them.  

Is there any risk of me going?  Could they say that I am frequenting a "prositiution" place?  

This is a place that has been around for a few years.

Thoughts?  How can I protect myself.  Even a normal massage place in that sense could be viewed as a prostition place if they offer it and we do not know.

In any local where you pay to receive some sort of sexual service, there is a chance of you being arrested for this.

 
However, if the place has been around a long time, and no reports of arrests, then the probability of you being arrested are effectively nil, and you shouldn't worry about it.   Heck, there's a place around me that's been doing the old rub and tug routine for about 50+ years now, and they've never been busted.   A gal who works there says she has been told that the local police tell them that as long as there is no FS, that LE doesn't care.

 
Still not a lawyer

Agreed and makes sense. But my issue is I am paying for a back rub and not sexual favor. (If the massage therapist decided to do a HJ during session, the. It is up to her.  

I am just concerned they bust the place while I am there and slam me with a charge possible?

If you are in there when the place gets busted, then the odds are that you will be busted also.

 
Call Bob Kraft and ask him for the phone number of his lawyer.

How do I get a hold of Bob Kraft

You have reviews so I don't think you can get a job at a spa and "get a hold" of him that way.  However, ...
.
Run a 4.0 40.
Bench press 225 x 55 reps.
Vertical jump 50 inches.
Run a 3.5 20 yard shuttle and a 10.0 60 yard shuttle.
Palm a 25 lb. x 16 inch medicine ball.
That will get his attention.
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Do well here: http://www.topendsports.com/sport/gridiron/combine-quarterback.htm
and he'll call you.

I thought you were serious.  LOL  
I am a john, not a provider.    

I was asking as a John, not as a provider... in case it makes a difference.

someone about 50 yards away while 7 - 300+ pound palookas are barreling towards you.

I wasn't clear in what I wrote. I checked and saw that you AUTHORED reviews = client, not Provider; I knew that. Hence: You will not get "a hold" of anyone by offering HEs at a spa.
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My final link was to the NFL quarterback combine tests. Do well there and you're in like Flynn.

Your chances of being there during a police raid are miniscule, bordering on infinitesimal. I don’t know where you live, but how often do you hear about massage parlor raids in your area? And then what is the chance such a raid occurs while you’re getting a handy (if you’re laying face down with a towel across your ass they have nothing to go on)? I’d say the odds are in the tens of millions to one that you have any legal jeopardy. Just my $0.02.