I did too until I read a comment from an IT worker who said that most of his time was spent connecting up customers who mis-spelt their email addresses when registering ..........
Aah.... but you see, you should have no sympathy for the worker whose employers can't write an adequate functional specification.
With a system thus :
(1) User completes form, entering email once, hits submit.
(2) System generates sends email with a unique single-use link
(3a)User receives email, clicks link, email therefore validated and account activated
-or-
(3b)User fails to receive email, link expires after X hours. User gets the chance to register again, no slave needs to be employed by the company to clean up the database.
The problem is averted.