Thank you everyone for the help so far!
As for JMT21's situation:
At first It seems that it would be legal, considering the commercial pilots did not advertise or seek the customer to be flown back home. Also, the plane is being provided seperately.
Yet this sounds like a trick question...If a commercial pilot gains a reputation too transport anyone anytime in their aircraft, the pilot could be considered a commercial operator. The pilot is being compensated by the flight time, and transportation back - still, since this is a one time flight, I believe this to be a legal commercial operation, and can be conducted under Part 91.
??? well??