"Sorry, I can't short-check bags. "
I have about 22 hours in SIN between flights, flying MSP-DEN-LAX on UA then LAX-NRT-SIN-CMB on SQ all in F. At UA counter in MSP was told , "They're looking at all our jobs in the merger and I'll lose mine if I do stuff like that." actually I think SQ can pull it for me, but this was an interesting conversation at least!