You're right. That is standard for a text box. But the email field, which is a textarea element looks like a text input field, where pressing enter would normally submit the form.

I must have used a lot of non-standard websites in the past I guess, I definitely would have expected hitting enter to have submitted my email.

Hopefully he wasn't filling out the Sensei form...

I'm teasing. I'm sorry, it was too easy and I couldn't let it go.