Recently (during last two weeks or so) a lot of such suspicious traffic started appearing in Google Analytics as various versions of Internet Explorer, not only 7. We were forced to filter out IE completely to just calculate stuff like conversion rate. Great that legitimate traffic from IE was negligible anyway, but who knows how much of this traffic is still hiding there as some other browsers?

Thankfully, as far as I know we don't do any retargeting campaigns right now (but I think we did in the past, and we were targeted by those IE7 bots in July as well), but it's still awful PITA to deal with it in analytics data.

So, I'm seconding your comment completely.