I once offered a friend a ride to the airport. He declined since he already had a ride set. Then shortly before the flight, he calls and asks if he can take me up since the other guy cancelled.
I said sure and drove him to the airport for his flight. As we're saying good bye, he tells me "your a life saver, I don't know what I would have done without you" me thinking I know what you have done! shell out a whopping $40!!
I agree with the OP, for the most part these should be a thing of the past. To me, when someone makes it clear that they want the ride purely for economic reasons, I have even less interest in taking them. I think it's selfish too to assume other should spend their time so you should save a dime.