Only locks login for existing username?

Apparently the plugin only locks logins which attempt to log into existing username (e.g. admin). If someone tries to login with non-existing username, the plugin won’t lock the attempt no matter how much they try it.

I think this would make the trespasser able to figure out which username he should keep on trying and which he doesn’t have to.

Is it possible to lock *any* attempts on login, no matter whether the username exist or not? Adding it as an option in the setting would be nice.