The you wrote is gone but I saw it on my email notification.

The reason **I** prefer an if statement is because of readability and being explict. 
You call it "EMAIL_REGEX" but it's not really that yet. Writing a regex on email addresses is genuinely hard and quite approximate. 

I think a lot of my objection is from the fact that the `EMAIL_REGEX` is defined many many lines away from where it's used. If it was right there in the if statement you could more fluidly read what it tries to do.