Nanpa?
It's actually quite common, but it also depends on the place.
You're a woman in the middle of Tokyo? Or on vacation in a popular spot alone or with a few other girlfriends?
Expect to encounter these guys every day, and I'm not exaggerating.
(There's a reason why the "Guys hitting on the FMC in the usual beach-themed episode" trope is so common.)
You also have to be very careful of Butsukariya (guys bumping into you), Chikan (groping), guys in cars stalking women, etc., etc.
It doesn't help that there are also women who use these dudes as a way to get a free meal or even a place to stay that night, in exchange for sex, which motivates these dudes to keep trying. Obviously, I'm not putting the blame on women, that would be a mistake, but I mean in the sense, that the entire system actually works for them in one way or another.
That being said, we focus on Japan because of the media we're reading, but the reality is that, pick-up artists are just about everywhere