I'm going off my previous experience as a moderator - which I was on and off for quite a while in Community, American AAdvantage, and Women Travelers at various times.

I can recall receiving less than a half dozen complaints about signatures during my tenure as a mod and unless my my memory escapes me, every complaint came from AA and had to do with member signatures referencing suspensions, other members, or other verboten topics. Now I guess someone could post photos of a suspended member and that might violate the TOS, but its a stretch.

I recall ONE other complaint about signatures that I received as a mod and that was a member who had posted a link to a site where he stood to have personal gain. Again, I guess someone could post a picture of something for personal gain, but I don't see that being a pervasive issue.

Finally, on the recollection front, since I was a moderator until very recently, I have pretty strong recall of topics discussed privately among moderators both in privleged exchanges and at moderator DOs, and I do not recall signatures being anywhere near the top of the list of problem areas that moderators had to deal with. Conversely, I seem to recall that the preferred method for dealing with problem signatures was to email the member and ask them to change the signature and barring cooperation, a senior moderator deleted it for them. Given that mod tools allow for editing of posts or temporarily deleting a post - and given that some members are QUITE fond of using the Report Bad Post option anytime they find anything whatsoever that they find questionable, I have a hard time believing that this is going to be a major time drain for moderators, but again, I'm going off my own experiences.