I would be against automatic bannings. There are lots of reasons why a post can be deleted. I got deleted, for example, some posts because I discussed with a member declared persona non grata in this forum (some may know who he is ). Some may want to get posts deleted because they wrote personal information in posts, etc.

What could be done instead is to give moderators an automatic "hint": if (e.g.) 10 posts of a single user were deleted, a checkbox could appear which would ban the user (or delete his signature), but the final decision belongs to the mod.

@vphasitha01: Good additions, thanks!