I fully understand Captain's Authority and all that, but:

Any pilot who willingly leaves a jumpseater behind when they could otherwise carry them is an unprofessional, selfish jackass* in my opinion.

Neither management or the flying public gives a damn about flight crews these days...all that's left is professional courtesy. Once that evaporates, what's left?

Its also clear that such asshattery isn't exclusive to ASA or regionals - pop over to the Cargo forum and see the thread about FedEx 777 captains refusing other FedEx pilots the jumpseat because "there's no room".

*exclusion for scabs, "listers", etc.