Yeah we do....although some dipsticks dont seem to bother when they have bought it.
I sold my Honda S 800 to a guy and did the notification thing. He didnt bother to change it and then a new rego rocks up in the mail about 2 months later.
I ring motor rego and they said I could send it to him or cancel it and get a credit....mmmm tempted but didnt and mailed it to him.
He is trying to sell it on ebay again now and I cant wait to see what happens next!
It seems that despite you notifying of disposal (good protection against speeding fines etc) you do still have the authority to stop rego until they lodge their papers!