DEN-DRO - I asctually haven't flown this route yet but I believe it's a pretty short one.
As stated yes, on short legs, the MLW of 34,500 can possibly become a factor with lots of extra gas on board. But from what I've seen so far, typically the MZFW of 32,000 lbs becomes the largest factor...
Off the top of my head, I believe one of the APU equiped birds weighs about 23000 lbs (operating), 37 PAX and 37 Bags weigh 8325lbs, therefore right the ZFW is 31,325... When was the last time you saw 37 PAX with only 37 Bags? The older birds, like the ones operated in Denver, are a couple thousand lbs lighter, ant typically can take 37 PAX, a J/Seater, and 45+ bags without exceeding MZFW. (of course out of ASE, EGE, etc... Performance data can greatly reduce the MFPTW in warm WX, tailwinds etc for obstacle climbouts)
But my point is this:
The MFUEL on the short legs is pretty low, usually around 2100-2400 lbs. Because of this, MZFW 32000 + MFUEL 2400 = 34,400 (100 lbs LESS than MLW) Therefore regardless of fuel burn, MLW never even becomes a factor.
I'm not 100% sure what dkwid meant because, I can't imagine a MLW issue without like tanker fuel doubling min fuel.
If you were bumped from the jumpseat on this flight, I'd assume most likely it's because the capt elected to Tanker a whole bunch of fuel. He/she was probably never told to expect a jumpseater (our great operations dept).
Hope this clarification helps....
SG
