We always push registry changes through our desktop management tool Desktop Authority (
scriptlogic.com) with no problems.
Special "Registry" object makes this a snap.
Just select hive, key or value and operation (add, delete, write). After that with validation logic you can choose which computers will recieve this new changes at logon.
You will be able to modify registry even in the case when user doesn't have administrative rights or special permissions for this - it's very useful function.