Now, you know I had to jump in here !!!
We have four self serve lanes at our walmart...one employee monitors all of them. As a customer, I can't stand them, find them very impersonal. As someone who has worked as the "human" on them, it is very hard to help everyone at the same time.
They really are amazing machines, though. They "know" how much each product is supposed to weigh, so there should not be any "cheating". On our registers, a yellow light flickers when someone needs "human assistance". This is definately the wave of the future in retailing.
Steph, in the layaway, they probably deactivated your item on the way into lawaway, not on the way out as it should have been.
That is why you didn't set off the door alarms when you went out.
If you hate it, complain. (To the home office of any store, doing it at store level is useless !)
Happy Shopping !