Policy says they should insist on the latter.

I've asked for short checking twice - both times with a long layover (arrive LHR 10 a.m., fly out 5/6 p.m.) - the first time from IAD for no obvious reason, the second time because I'd bought medicine in ORD and the bottle was too big to carry on with me.

On both occasions I was able to do so, and I was a gold travelling business class on each occasion. I don't know if any of those factors were relevant - in any event the bag was small enough to carry on so I wouldn't have been stuck.

(But I am a big fan of travelling hand baggage only if you possibly can, regardless, especially in Club where there is no shortage of space).