You have to really feel for this Lyft driver. They pick up and drop off passengers, trying to make some side money to pay the bills. Then something like this happens, and naturally, folks assume they were the last person known with someone like Kenzie and it raises their suspicions.
I know of a couple of people that do Lyft and Uber. On their phones, they have a right to choose who they pick up and given the time of pick up- they do not see the name of the passenger. The last I knew, they did not know the person's destination until they got in the car (two months ago, this was the case)- that was frustrating for someone I know that does it, because he was at the end of his shift, and noticed someone was waiting for a ride for a bit, so he figured he would do it. Well, once they got in the car, he found out their destination was an hour and a half away- he was committed to it, so he had to complete the ride. By the way, they don't get reimbursed for the gas money, which I think is terrible if a passenger is going that far away, the least those driver places could do is reimburse them for the return trip for the gas.
Once they get to their destination, the Lyft/Uber driver signs off once the passenger is out of the car, and they either go to the next destination for another passenger or sign off for the night.
I don't know if this information helps with others questions about how Lyft/Uber works, but figured I would discuss this, to clear up any confusion as to how they work.