A few times I've accidentally sent an email without remembering to check and change my from address to the account I am using for that particular service/sender.

It would be good to have an option to force you to manually select a specific from address before letting the email send.

In short, the "default" email address would be blank if you enabled that option. When you draft an email, it won't send until you've selected which address you want to use.

This would (or could?) exclude replies where the email has come into a specific address. New emails only.