Who said stringent UI validations only make rock solid applications?
There are cases where the name field should be able to take first name and middle initials and the best design would be to allow intermediate spaces too. Similarly, allow free form telephone number instead of masking them country wise since there are cases where phone numbers are shared with a pilot number by an organization and extension number might be the only way to route calls.
http://www.community-credit.com/ is a very good example of having usernames with embedded spaces since migration of their old login system to new one. They have pleasant script validations which don't scare you with popup message boxes but just flag the required fields.