Let's leave aside the fact that for decades Tuttle has come out with a series of books called Making out in (Thai, Japanese, Tagalog) that have a healthy selection of words that can easily get the unwitting user in, as they say in oilworker bars, " a world of hurt." And if the curses and epithets don't provide enough danger to human life, there are a generous number of break-up phrases in these best-selling little volumes that are easily as dangerous to use as slang, curses and epithets. And as far as I know, there has been no significant number of slaughtered foreign innocents found with copies of Making Out among their personal effects.
In Thailand, what will save users of Outrageous Thai from certain death are those same tones that render their requests for khao pat gai and a Coke completely unintelligible to native speakers. If a faulty tone can turn an innocent phrase into an obscenity, then certainly foul language can become endearments under that same alchemy.
When I first came to Thailand, I was told to yell "Fire!" and not "Help!" in Thai if I found myself in any sort of danger on the street, because people will respond to the first and ignore the latter. Even as fresh of the boat as I was at that time, I knew full well that my attempts at yelling "Fire!" could just as easily result in shrieking "Pipe wrench!" or "Chastity belt!" (Luckily for me danger on the street is about as rare as a farang who has mastered all of the tones in the Thai language.)
It also occurred to me that there is a built-n safety measure that comes with learning another language while living in the country where it is spoken. All of the truly offensive phrases that come to mind during the first years of living here--and in my case there were many as I wallowed in culture shock and frustration--are ones that you only have the ability to use when you understand the weight that lies behind them. And with Thai, tones provide an added kill-switch.
The day that I learned that I could manage a sarcastic phrase in my new language was a day of shock and awe for me--fortunately during the yawning gulf of time that it took to be able to do that, I had also developed a new perspective that kept me from using this achievement very often. By the time the purchasers of Outrageous Thai have mastered the tones that will make their slang, epithets and curses intelligible and offensive to Thai people, they will either have moved on to another global neighborhood or will have lived here long enough to know the hazards affiliated with their use. Tones--can't live with 'em, can't live without 'em--but sometimes you just have to be grateful for the damned things.