[goto11]

Sure, but the most common typos would just result in a wrong address which is still syntactically valid. That is why the address should be verified by sending an actual mail for important stuff. This is also the only way to protect against fake addresses, since anyone can come up with a fake address which is still syntactically valid.

I do like to check for '@' to enure the user have not entered their name or something by mistake, but beyond that the syntactic validation does not provide any value.