From: "Ryan W. (Merovingian)" bigwiki@earthling.net
I've noticed the same thing. I assume that it's a "clueless newbie" just
seeing if the "Edit this page" button really works, and then running back to undo it, so that (s)he doesn't get "yelled at" by a "mod". I think the uninitiated think Wikipedia is a lot like a forum, where we kick out just anybody we don't like.
The "edit this page" tab is as tempting as a "wet paint" sign.
Except that you have the opportunity to remove your fingerprint afterwards.
I've assumed it was in fact _responsible_ behavior. The first edit is just "being bold." The second is being responsible. I've occasionally complimented anons that did this.