In JIRA 5.1.1 if you create a user and add a trailing space to the email it will save without issue. In the UI, it looks like everything is ok. However this will break issue creation from emails since the email will not match. A select * from cwd_user; produces a result which when checked in hex reads a 2009 separator instead of a 09 separator. See the attached file in a hex editor for user 3's email.