What you say is pretty understandable, but I dont think theres a way to completely avoid spam. As some people said, those threads are already considered as spam, so they should get closed as soon as a Mod sees it. I dont see more efficient ways to do it other than maybe hiring more Mods so spam get spotted faster, or have a way to check and verify everything that is says in a post. Unfortunately, I would be surprised if there was a way to pinpoint excactly was is spam and what isnt. Lots of lure thread or thing like this, and there are not necessarily spam threads. Well at least I dont consider them as spam.
But concerning your idea, I would like to hear how you would make people ''not able'' to do such post. Like for example the posts you linked here are all obvious spam, but what would be your way to be sure this kind of thread cant be post, but at the same time be sure to not compromise the ''liberty'' of posting things the way you want.
Anyway, lmk what you think
