I can confirm the US-Procedure: When I picked up my brother-in-law some years ago in Seattle-Tacoma, I found out, that his baggage already had arrived on an earlier flight...?
At the regional carrier I work for in Germany, it is common practice, do do a headcount before taxi.
If the number is incorrect and ground staff confirms, that a pax is missing, there has a baggage ID to be performed to offload unaccompanied baggage. I feel much safer with that procedure.
[This message has been edited by Midnight Blue (edited 31 May 2001).]