I can't talk about Thailand, but I live and work in Subic Bay. Neither can I offer a woman's perspective - although I can pass on what I have heard, or have seen.
The 'vibe' here in Subic is very different to Thailand. There is a sex trade here and it is common to see older men (think, retirement age) with young (legal age) girlfriends. Some are tourists (the girlfriends 'Rent-a..'), but many others live here... and they are married to those young ladies.
It's hard to get your head around the financial and cultural issues that foster such a great age disparity in relationships. That said, these girls are mostly very happy, they enjoy a level of security that would otherwise be unobtainable for them. They know their children will be raised to a better life, with greater opportunities. For the most part, they will be loved, respected and cared for.. often far more so than they might enjoy from a local partner of the same culture. In many cases, the western boyfriend will pay for their girlfriend to go through college - offering them a real long-term future.
The only time I see those girls upset is when their western boyfriend breaks their heart. Genuine heart-break because the guy, many decades their elder, ended a relationship. There's nothing faked about that.
The bar culture here is an interesting study. I've been here a while, so have had opportunity to see this life 'behind-the-scenes'. I do occasionally drink in the bars (some have great live music) and and know many of the staff as genuine friends: the (western) owners, the mama-sans and the girls. The owners demand their girls are treated with respect. The 'mama-sans' are called that for a reason - they protect and guide the girls like a mother. I don't envy either the owners, nor the mama-sans, for having to deal with the dramas and demands of dozens of 18-26 year old girls....
I do not engage the services of the girls - they know that, so I don't get viewed as a 'customer' and enjoy a more genuine relationship with them. Most are sweet, caring girls who do their jobs to feed their children and, perhaps, meet the foreign 'man of their dreams'. I end up as a 'relationship counselor' far too often. Most enjoy their jobs, get treated with respect and enjoy an income far greater than they could otherwise hope to earn. There are times I go home with my cheeks aching from laughter... or spend an evening discussing politics or culture etc with a 'dancer'. It defies preconceptions. Some of the girls are college educated. One friend is a fully qualified nurse..very intelligent, very articulate and a good conversationalist...degree educated, but unemployable due to that job market being saturated here.. she's a former bar waitress of several years.. but now engaged to, and very happy with, a retired US Navy officer. An observer might scorn them - a large age gap - but the true story is quite remarkable and heart warming.
I don't see under-age prostitution here. I know it probably happens, but not in the 'main' bar areas. I assume it's a shady back-alley bar sort of thing. All I know is that the Philippines authorities have a very firm line on under-age sex. You'd need to be an idiot to cavort, or be seen in public, with an under-age girl. It really isn't an issue, but may appear so, due to the fact that many Filipino girls look considerably younger than their actual age. My Filipina partner genuinely looks mid-twenties... but she's 40 (the same age as me)...and an ENT/Cosmetic surgeon. Guessing her age is not made easier due to her passion for all things 'pink' and 'Hello Kitty'. It pays not to be prejudiced, as assumptions can be wildly wrong.
For a visiting western female, I think it'd be fair to say that there is little cause for concern about harassment. I know several western girls who live here (Subic) and the only thing I hear them complain about is the impossibility of finding a guy. It must be depressing to have 'the tables turned', but western girls really are the 'chasers' here... not something they'd be used to at home. Those western girls that I know here also drink in the bars and also have friends who work in those bars. When you can see beyond the facade and cultural stereotypes, the reality is very different... very understandable and not very objectionable really...