My gmail address gets used as a throwaway rather a lot, and you'd be surprised at the number of sites that don't bother at all.
This message was sent to you ($firstname.lastname@example.org) because you are a valued NBA fan registered with us and we wanted to wish you a happy birthday!
Registered email successfully updated
Your email address for the account meleonaz has been successfully updated to $email@example.com
We got a request to reset your Instagram password.
Thanks so much for joining Pandora! We're very happy to have you on board, and we look forward to providing you with endless hours of great music listening and discovery.
Many more sites will still create the account and let you use it without me validating the email, and many more provide no means of saying this *isn't* their email.