In the PBEM I'm in, I was told that as long as they don't directly violate any of the general orders then it's fine for a starfleet officer to be as motivated by profit as they like. They can be out for as much as they can get off duty.
Additionally, I was told that starfleet officers do in fact get paid for their work, and Picard's views of mankind leaving behind materialism are nice ideals but aren't universally practiced by starfleet officers.
For the life of me, I can't find anything to support that view, and I was hoping that some of you could share your thoughts on the subject.
-Christian