When I lived in Alexandria, Va., the local bus system was vastly improved with more frequent service and, with a grant from the city, became free to ride. In some places, I think that free transit would attract people who are not on board to go somewhere. However, I don't recall seeing any shady characters. I would have cheerfully continued to pay my senior half fare, but I heard that so few people had been riding the bus that the cost of fare collection outweighed the revenue. However, I had been not riding Alexandria Transit ("Dash") much not because of the cost but because service was skimpy, with some routes running once an hour. If a transfer was involved, it was often faster to walk (and, as now, I was living car free). But once we had service every 15 or 20 minutes on some routes, I rode a lot more. The free service helped in another way. If I added value to my Smartrip card, it was supposed to show up within a certain time, but it never did appear the same day, so I always went to a Metro station and used a fare machine, which always added value to the card immediately. However, I lived miles from the nearest Metro station, so it was helpful to have free travel on Dash and also not have to pay for a trip just to reach a fare machine, though with planning I usually incorporated that travel into other trips.