Personally I think it’s always good to say what something is for or not for. It doesn’t mean it will or will not happen (it will). The point is to make a declaration of intention of what the culture is as a backstop. Somewhere down the line something always goes wrong. Messaging like this is not, for me, anything to do with prevention, it’s to do with articulation. It says “you signed up for this and made this covenant”. We articulated something and you made an affirmative response that you understood. Ultimately, it makes moderation easier. Still doesn’t help with the tradeoff problem that’s everywhere online.
Ps. I might be alone in this, but where I’m from “hookup” and “hooking up” is not meant in the way that it is being used in this thread. I’ve always used it (as have my friends) to simply mean “I’m meeting that person”. There’s no sexual/dating meaning whatsoever. I live in the UK, probably in a cultural/linguistic bubble. It’s always interesting and / or confusing to realise that people are talking about something else.