With Surveys :

1. Allow to create Survey permission : you can create and manage your own surveys
2. Allow to update ALL survey : you can manage all surveys
3. You can create Survey and set owner to someone else (even without any surveys permission)

With Users

1. Allow to create user : no way to create user
2. Allow to update ALL users : you can only manage you own users

I really think we need same system for Users than for Surveys …

Have some user allowed to create and manage their own users but not the other on …