Seriously, let them join, they make their own servers and have fun there, they won't bother you too much, they deserve to have fun too, right?
Personally, I would love it if Blockland would have over 100k players, there might be alot of dumbasses, but seriously, in that mass, there should be some people you could become good friends with.
Just stop making drama about the ammounts of players...
tl;dr:
Alot of 8 year olds can have fun on Blockland too, why should we take their fun away?