they can continue to post in it. without bumping
I personally don't think that most people would click the box, or even acknowledge it.
And even if many people did, there would still be new members who didn't know better, or spammers, or those who just don't care who would continue to bump the topics with each post.
Same really goes for Spam topics.
The spammer in question isn't going to spam the forums, but decide to be polite and not bump his topic when he posts in it.
If the Forum Games are one of the main issues behind wanting one, wouldn't it just be easier to include a new rule, stating that they have to absolutely go in the Community Projects forum or something?
And have moderators move the topics over if posted in the wrong place by accident.
And repeat offenders may face bans or whatnot.
I get the reasoning behind wanting one, but it seems like something that will just get confusing or will be ignored.
Idiots and new members and whatnot won't use it on topics where they should.
You'll have people who post in topics without bumping it, which means people won't even find the topics later on.
It'll make no difference to people spamming topics.