How high-traffic web sites still not obfuscate these errors, or even allow them to happen in the first place, is far beyond me.
It's annoying to look at, and I wouldn't do it... but it doesn't really matter.
I hate to beat the cliche, but just one of the reasons I feel happy when using most of Apple's products: they just scream that even the details were very much thought about.
PS: No, the phone has never been jailbroken.
(Not that I want to do it..)