@Acolytus I swear I've seen something like that in other romcoms even though I can't specifically refer to one.
Random scum harassing girls during "events" (beach, summer festival, hot springs,...) is one of the most tired tropes of romcoms, so more imaginative authors try to put a spin on it. Including what you already mentioned, or the guys being extremely shy and just being awkward about approaching strangers.
It's also funny how one of the general themes of any given romcom is to not judge people on their appearance or the rumors around them but these kinds of "jokes" rely entirely on the dudes' appearance. It indirectly implies that approaching a stranger at an "event" is categorically wrong...