git over command line: Alt + Tab(shell), git commit -a -m "<message>" RET
You see the problem. Even assuming the message is short and typed on the command line without invoking the editor, the number of keystrokes is more. Of course number of keystrokes is a minor thing, when you compare rebase and other operations.
Right on point. Also its at the mercy of the application and even then one there must be a trusty third party who can certify that an application follows the spec. This is not practical.
The reliable and practical way is to have a ad blocker at the kernel level similar to browser ad blockers.