Re: "Wrong" email addresses
I know someone with an apostrophe in their email address, due to their irish O'whatever name. Despite the fact it's 50/50 whether the receiving email server will accept it or not, the admin has never enforced a policy that removes it when creating accounts.
What annoys me is when you have to login somewhere else and it's not obvious they have a different country keyboard layout. Those special characters are not where they are supposed to be. So do I devise new passwords which only uses the characters that don't move say between US and UK layouts, thus weakening the password due to less entropy, or use them and struggle to login some places?