I don't think there's anything wrong w/paying the driver; not everyone has a reloadable card, plus if you're a tourist you wouldn't want one. When I visit relatives in Seattle, the buses there still take cash, but they also have the reloadable card like you talk about. It was tricky when I was in the UK on my last day, my travel pass had run out, and I figured I could just pay cash to get the bus to get to the train to get to the airport. Nope; the bus didn't take cash. Luckily a friend knew where I could go to buy a one day travel pass (which I couldn't have purchased on the bus). this is where cash can still be useful.