ive not read all the replies, so forgive me if this has already been said, but its not just female therapists who get this, and its not just from perverted males.
It is a shame, but I can state that there is discussion with the police regarding 'legitimate masseurs' and those who say they are, but are offering extras.
Unfortunately wording such as non-sexual service doesnt get through to some of the idiots that call.
It did happen to me a while ago, relating to Myofascial Release, im not going to go into the conversation but when i realised what i was being asked, i was fuming and put the phone down, my colleagues thought it was highly amusing!
Dont let it get you down, its good to have a rant though!
There's probably some underground way of communication that says if you say it's not sexual then it is. A sort of double bluff that you are using to allow your advert to be accepted when really you are offering a sexual service.
It's not even that underground with the internet and search engines - someone searches for sexual massage your webpage says all massage is non-sexual - it will be presented in the search results for sexual massage. The not terribly bright person doesn't bother reading the context that sexual was used in and just thinks 'these are results for sexual massage I will call that one!' they're already convinced that is what it is, they've got the results from the search engine, you act dumb when they call, you're being discrete! Many people just hear what they expect to hear.
I think it's even more of a problem listing in an online directory that requires all listings to include 'not sexual' - so many of those are, that even if they read the context it is ignored, and then that mindset is applied to any website...
It's less of a concern for printed material - you don't come up in search engine results, if they read sexual they've read the context it is used in, then I think there is still a bit of the don't push this button syndrome, but it's a tiny percentage compared to the bulk of the every hopeful search engine results.