PVD still has the baggage/X Ray machines in the lobby. After you check-in at the counter and check your bags and they are tagged, YOU must carry your bags to the X Ray machines. Then you must wait until they clear your bag(s). I have used locks, and the few times that they had to open my bags, I was there to open them.
I know this set up is very rare. In no other airport that I've been to is this done.
The airport in Green Bay (GRB) has no X Ray Machines for checked luggage. It is a small airport. You check in at the counter, get tags for your luggage and walk the bags a few feet to a checked bag screening. Then they visually check the bags, will take off the locks using your key if needed, check the luggage and then put the locks back on. You are expected to stand there while they check the luggage. Then they put it on the belt and you can proceed. They do have the xray machines for carry on luggage. I never have a problem leaving from GRB but have on the return flight. Most of the bigger airports that have the xray machines in the check in area will let the locks on if you stand and wait until they put them through in case they need to open the luggage. There have been a few agents that warn me that my locks might be cut off but it has not happened yet.
Dawn