My first scam artist pax

This is my third weekend driving for Uber. I'm in a college town, and all of my pax thus far have been students. Tonight, I had a drop-off at an apartment complex that clearly had a party going on. As I went to pull away, a male student knocked on my window and asked if I was Uber. I said yes. He asked if I could drive his friends for cash. I said no, but if he put in a request through the app, I'd likely be the closest car and would get the ping to pick them up. I rolled up my window and drove away to turn around and leave. Sure enough, a ping came in from a female rider at that address. I accepted. The guy and a girl got into the car. I asked her name; she gave a name matching my rider, and confirmed my name. I confirmed their destination, and we started off. About a block down the road, the trip was cancelled. I asked the pax if they cancelled the trip. They said no, and that they still wanted to go to the original destination. In the moment, I decided to finish the ride (about a mile and a half) and deal with Uber later.

I suspect that a) the girl that booked the ride was not the girl in my car, but a friend of hers, and b) the friend thought she could get away with cancelling the trip without a cancelation charge because it was within 5 minutes of requesting. Unfortunately for her, I had already started the trip, so she was charged the minimum fare.

After dropping them off, I went offline and sent all of the details to Uber.

Am I correct that basically my 2 options here were to do what I did, or to stop the car and kick them out immediately? What are the chances that Uber will adjust the fare to the correct distance and time? I also requested that Uber rate the user 1 star for trying to scam the system. Any chance of that happening? I don't want these kids showing up in my queue again.

UPDATE - just heard back from Uber. They adjusted the fare, but because it was a cancelled ride, I cannot rate the user. I will surely be wary of Hannahs from now on...

Thanks, everybody.