Interesting thing happened at a checked-bag inspection point at an airport in Canada today. The background: an American passenger arrived from the States and showed Customs his bag. They found several "prohibited items" (in this context it means prohibited as in not legal to posess anywhere in Canada), numchucks and throwing stars and such. He made no attempt at concealing so they told him they'd hold it there and he could take them back to the States when he flew out.
On the day he was to fly, Customs took his bag down to the check-in area with him and notified the screeners of what they were doing. The screeners checked the bag and, yup, of course there were still prohibited items in there. They called the RCMP. The RCMP arrived and told him he was breaking the law but that since he hadn't tried to conceal and had been co-operative that all they would do is seize his items.
To me it seems like the screeners over-stepped their authority (and in the meantime made the Customs inspectors look like idiots) by alarming on legally "prohibited" items but not items that were on the Transport Canada checked-baggage prohibited list. I'm in the process of going through the Aeronautics Act and some other documents to see what the law says on this matter.
I woulda been screwed in Britain last year if their screeners had acted this way as I accidentally brought a Leatherman with a >4" locking blade with me in my checked-bags.