This feature is intended to prevent you from accidentally editing using the wrong account, or accidentally revealing your IP address by editing while logged out – for example:
- in a pre-IP-masking world, as a "normal" user, if you log out in another browser tab (or clear your cookies, or they expire, etc.), you'll get a warning message before saving, so that you don't accidentally edit as an IP user
- as a WMF employee with a work account and a personal account, if you log in into another account in one browser tab while having the editor open in another tab, you'll get a warning message before saving
For IP masking, we'll just consider switching temp accounts to be the same as logging in/out.
