I have a friend who works for an NGO in Bangkok that deals with human trafficking and prostitution and a great deal of that has to do with issues of violence against these people. In terms of this topic, Bangkok and Thailand in general are interesting for several reasons. The most obvious of course being the sheer number of people who make a living in the sex industry. A lot has been done to curb underage sex-work, but people from around the world still go there to have those kinds of encounters. However, poverty is not what it once was in Thailand and that's a major factor in the decrease in the permissive attitude toward child sex that was prevalent in the past. Unfortunately this means that much of that "industry" has moved next door to Cambodia, which is still recovering from the Khmer Rouge regime and the awful way that the U.N. handled the post Khmer Rouge years.
In Thailand, there are plenty of women, men and transgendered people working in the sex industry. I'm not clear on the laws regarding prostitution, but they seem fairly lax. The NGOs do a lot of work there spreading information on safe-sex practices and running clinics and such, but a good friend of mine who works for one of these NGOs told me that at this point many families are no longer ashamed that their family members make money in this way. This is not to say that they are proud, but rather accept it as a necessity. In that line of work a person can make many times what they might be able to otherwise, at least for the people from impoverished backgrounds with little to no education.
In regard to violence against sex workers in Thailand, the police tend to react very quickly to violence against these workers as they are a major source of tourism. These practices have spread to other parts of SE Asia as well, whether or not prostitution is officially sanctioned by their respective governments or not. I really wonder if these areas would fully embrace sex tourism trade if there were no social stigma or consequence attached for them.
On the other hand, Bangkok's reputation as this kind of city has created a certain cachet or mystique that people the world over have recognized. In movies like "The Hangover 2" a stylized representation of what Bangkok is like is the backdrop for what is essentially the plot of the first movie. It's all supposed to be in good fun, but its impact has done very little to represent the reality of what Bangkok is like and unfortunately, there are travelers who are now going to Bangkok for that kind of experience. In my mind, that movie serves to dehumanize the people in the sex trade. It paints them as "others" who exists only for "real" people to have adventures with.
Another interesting angle on prostitution in Bangkok in particular is the growing prevalence of university students soliciting tourists. Often they are looking for money to pay school fees, or sometimes even for pocket money. It's hard to say what would happen if all prostitution in Bangkok were to suddenly stop, but the impact would be very significant. It's too bad, since Bangkok is a great city on its own, but with the sexual tourism industry being what it is, parts of it are a bizarre, sexual Disneyland. To continue with that metaphor, the sign above the gate might read "The Happiest Place On Earth" but the reality of the interior is anything but. Thailand might be referred to as "The Land of Smiles" but as in many cultures, it's what lies behind the smile that really matters.