I came across a couple of dodgy edits in the review queue, both of which I rejected and both of which ended up being accepted. The two in question are here and here. (Edit: Actually, I only rejected one - the other had been accepted by the time I clicked reject.)
I rejected them for two reasons. Firstly, they are dubious with respect to validity, changing "$a\in S$" to "$a$ belongs to $S$" or making a "3" in the title a "$3$" (which means that the front page renders slower for some) are invalid in my book. Secondly, and most annoyingly, is the editing in of some generic "help me!" line. If someone added this to my post I would be pretty annoyed - you are putting words in my mouth! (This second point is the inverse of this meta question.)
So I dug a bit deeper into their editing history and it seems that there are too many such banalities to undo (my patience is short - I would much rather waste my time writing this than do something boring like that!). And so my question is this: what should be done in such circumstances? I flagged one of the edits for moderator attention, but really what can a moderator do? Should I make a comment on one of their posts telling them that this is annoying me? But that is just spamming...