What Google has done, is add profile pictures for users, so if I'm emailing girlfriend@gmail.com I get her picture, but if I email giirlfriend@gmail.com, I see someone else's pfp which is enough to get me to realize I've spelled it wrong. I'm sure there's more they could be doing, but they're aware of the problem at least.

But that only works if you’re emailing from another Gmail account yes?