It wouldn't kill them to do a viewport check. I mean, unless they expect crackers to run their servers from a jailbroken iPad?
I also had to change my Yahoo! password for Flickr a while back, and I think the maximum length of my password was still at ~32 characters ... and there's not two-factor authentication to boot.
Yahoo! is very AOL-like still, which is one of those things I really, really hope Meyer can do away with.