>Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not

That is one of the milder error messages. I have an accented character in my first name and run up against this all the time. I used to screengrab and collect them, but it would have been easier to collect the sites which didn't object.

In the rudeness stakes, I think my favourite so far has been:

"Please enter a valid name"

although there have been plenty of others, nearly as insulting. I see the post is from 2010. I'm still running into this problem today.