How is it not allowed when clearily i didn't block him from expanding

I might have found a loophole about greifing. Is it Possible for to claim a land in front of someones base instead of surrounding thire base because it said if you surround the base then its griefing but technically if you only do the front they can still expand from the back. So yea is it...

i HAVE A OTHER QUESTION! Is it possible to get perm banned for building a moat around someones base while the moat is ur claim (ALSO I NEVER DONE THIS I AM JUST ASKINg)

I have a question. Is it possible to get perm banned for griefing for example building a wall around someones base.