Did I do the right thing? Should I have been more aggressive?

So here is what happened to me the other day. It was Tuesday AM and I was talking the Shuttle from that Parking Spot Garage to United Airlines Terminal to Catch my flight.

The driver of the Shuttle was doing his job and dropping people off at their terminals. It was early in the morning, about 6:30. When we got to the Delta Terminal the driver got out of the shuttle and helped a lady with her bags. She gave him a couple of bucks but then before he got back in the shuttle he stepped forward and picked up something off the ground. It was black and looked like a wallet to me. Then he got back in the shuttle and shut the door and waited to get back into traffic. While he was waiting a well dressed black man with a hat that looked like a french beret and a nice scarf and jacket came out and started to look around his truck for something he had lost. He seemed upset and I knew that what he was looking for was most likely the item that the driver had picked up. Before I had a chance to say something the driver pulled out into traffic and was heading toward the next stop which was my terminal.

This really bothered me so when I got out of the shuttle I mentioned to the driver that he should have given the guy his wallet. He told me he did not take a wallet and then pulled out something that looked like a black bag that you would put sunglasses or some other valuable items in. I was walking away from the shuttle and did not want to engage him, I just wanted to be his conscience.

Now my question to you is? Should I have said something earlier so the guy would return it when we were still stopped? There was a very narrow window to do that. Should I have said something right when he picked it up? Should I have said nothing?

I like the pay it forward type attitude. You see someone doing good and then you do good. I also like the Karma concept or what goes around comes around. These are nice ways to think and rationalize doing right but we all know that deep down good people will do good things and bad people will do bad things.

So what do you think?