Seattle used to have this for an area of the city. It was called the "Free Ride Zone" - and it had some unexpected consequences.
The primary problem is that homeless people would get on the bus because it's warm, and would fall asleep. The busses became rolling homeless shelters.
This caused other people to take the bus less, because of public safety concerns, as well as simple quality-of-life issues like unpleasant smells.
Eventually it was scrapped.
But this issue has been returning as it's now common knowledge that Seattle bus drivers are instructed not to collect fares from anyone that declines to pay.
The primary problem is that homeless people would get on the bus because it's warm, and would fall asleep. The busses became rolling homeless shelters.
This caused other people to take the bus less, because of public safety concerns, as well as simple quality-of-life issues like unpleasant smells.
Eventually it was scrapped.
But this issue has been returning as it's now common knowledge that Seattle bus drivers are instructed not to collect fares from anyone that declines to pay.