Bag Checked for first segment, carry-on for second
 

Today I had a ticket from LWO to WAW via VIE on OS. The equipment to VIE was an ATR. My bag was too big (as were most people's) and I was planning on ditching my last segment to WAW and to stay in VIE (which I did), so I asked just to check my bag to VIE.

The gate agent said no problem and checked my bag to VIE, but said I would have to get the second boarding pass there.

Can anyone explain why this is possible? Can one do it in the states?

Could it perhaps be because I had a (theoretical) 3 hour layover in VIE?
Was it because the plane bin size on the ATR wouldn't permit my bag as a carry-on but perhaps the equipment on the second leg would?
Was it because passengers could gate check on that flight (as with RJs in the states).

This is interesting because it seems more flexible than what we do in the states and also it would potentially allow people to ditch final segments of their flights and STILL get checked bags if certain routings are cheaper than others.

I am not sure where to put this post, but since it deals with baggage regulations and comparative safety/regulatory issues I thought this might be the place...