You forget one thing: People make typos. Assuming Sony blocks all LEN(TLD)>3, do you think they’ll lose more customers than they’ll lose from them not getting

You forget one thing: People make typos. Assuming Sony blocks all LEN(TLD)>3, do you think they’ll lose more customers than they’ll lose from them not getting their validation mail because they typoed their mail? I’d bet that the first group is far smaller than the 2nd. Now instead of blocking it would be nice if they just asked if you are really sure that’s your email, but it’s probably still better than just accepting everything and trying to send a confirmation, both from a business and from a customer-friendliness perspective.