chrome(ium) also throws up a big red warning page that you have to accept before you can proceed. many (most) users will go no further.
as far as whether a CA verified the IP address.. I don't think it's conclusive that they *didn't* verify it. most of these certs are on (consumer) routers, which have a default IP address. it's not beyond the realm of possibility that a CA verified that the IP address they're signing is the one the router uses. that's just as valid as the 'certification' they do for a domain name by sending out an email to postmaster@... and hoping 'postmaster' doesn't just click the link because 'it looked official' (and yes, I've seen that happen).
this is one of two recent problems that really have no good solution (read: the solutions are very expensive). firesheep being the other one, making session surfing ridiculously easy.
the only real, cost effective solution to these problems is an SSH style 'seen it' key repo in the browsers. the first time you visit a site with a self signed cert (which is otherwise valid), you get a very *non scary* warning that this is the first time you've visited the site. after that, no warnings whatsoever unless the cert changes. the problem with this solution is: IE6, IE7, IE8, Firefox < 4, Chrome < 6, etc, etc will still be throwing fits about 'invalid certs'.