Spending 20k abroad on sex may seem like a good idea but,....
You're right to highlight the risks and the dangers. The way I see it, if you're in the wrong place at the wrong time you're fucked, not in a good way. The same could be said of London though, the knife crime capital of the world, terrorist incidents, punters being robbed, ripped off, not to mention the countless negative reviews!
I take the optimistic view, a lot of these places rely on foreigners to bring in their cash and not just sex tourists. I was in a cafe in Agadir and some local loony starts giving me a mouthful whilst I'm drinking a cup of coffee, on my own. I'd given the waiter a handsome 50p tip the previous couple of days and he didn't want his generous tipper being put off returning. Local loony was told where to go.
I also think it depends where you're looking for company. The local women know foreigners have a lot of money and they want some, which means scoring with enthusiastic amateurs/semi pros is not difficult. You can chat online through different sites or use dating apps, a great many speak English, certainly in the Philippines.
Ultimately, safety is a matter of common sense. Don't go wandering around in the dark stinking of cash, don't paint a target on your back by upsetting the locals, getting drunk, loud or aggressive. Overall, I think there are fewer negative experiences punting abroad than punting in the UK. Maybe because if you have a shit punt it might have cost you £20/30 for a couple or three hours, compared to £150 an hour here. You can wander down to the seafront, have a cracking meal for a fiver and watch the sunset.