I'm inclined to think like you, but sometimes the numbers just don't work out for this sort of thinking.I have a contrarian streak, so I will add this.
Someone new joins the group and starts doing a lot of posts. Yes, it could be they just want access to the classified section, but, on the other hand, maybe they are just enjoying the forum and diving in.
Do you really want to be the grumpy old dude yelling, "GET OFF MY LAWN!"?
For example, in the latest case (@Kanon) with 1-2 minutes between posts, it just doesn't leave enough time to read the thread before responding. I suppose that all the reading could have been done ahead of time, then responses composed before actually posting the reply, but does that sound realistic?
I'm hoping that the warning that KiA issued is heeded and this new member will stick around for a long time.