Need option to Disllow Registering a Different Person

The new option for users to register another person is problematic in many cases, such as when the buildAmount hook is used to modify event pricing based on properties of the current user. I.e., in this case the user could register others with discounts properly available only to the user him/herself.

At a minimum, it is necessary to provide administrators the option to disable this ability. Another approach would be to provide an option which lets administrators force the user to log-out when using this ability.

I'm not the only one concerned about this: http://forum.civicrm.org/index.php/topic,13696.0.html