Thanks for the input folks - very helpful. So, the question is, on a booking like this (booked using multi-city function):
Journey 1:
A to AMS to B
Journey 2:
B to AMS
Journey 3 (17 hours later after an overnight):
AMS to A
The page that has been linked to is clear in stating that bags shouldn't be checked through, but agents at outstations may see it differently (I agree, a print out seems most prudent). Would an agent at point B in the above booking view journey 2 to journey 3 as a transfer, or does the multiple trips element make baggage retrieval easier.
Originally Posted by irishguy28
which is why they are now clamping down on short-checking of bags (for people who want to "jump out" at Amsterdam, they are increasingly attempting to hold baggage hostage
Ahem, I wouldn't dream of it ...

I'm naturally just asking out of hypothetical curiosity...
Originally Posted by irishguy28
(though at least starting from Antwerp rather than Amsterdam will mean connecting from/to a train at Schiphol, so no baggage delivery issues there).
I hadn't noticed this one - reading the "Travel by rail" page on KLM's website, I'm not altogether clear how it works - you pick up the train ticket up to 4 hours before departure from Antwerp station, and at AMS they need to see the train ticket (to prove you didn't start short) - but only at that point is baggage tagged and deposited with the airline on the outward bound? And on the return to AMS, you collect baggage as usual (and officially collect a ticket for the train back to Antwerp somewhere landside in arrivals?). Have I got the right end of the stick?