Participant status update is wrongly updating register date.

Currently when we do update participant status from -
1. Batch Update Participant Via Profile Or 2. Change Participant Status.
participant register date is getting wrongly updated to today.

Expected behavior would be :
When we do migrate participant status to "Pending" class in that case only we should update register date.
Since register date is the key to check the validity of pending registration.

Forum thread is here : http://forum.civicrm.org/index.php/topic,14644.0.html