I live in a nordic country, very proud of it's nature, and I know bus drivers.

In all honesty, I'd not be surprised if these cases were isolated, but that has been the greivance of these drivers.

The alternatives to this would be a heated hall, or finding a way to power the heating with renewable energy, but then again, diesel is cheaper than the alternative, and most of the passengers have no idea. There isn't any proper sanvtions to incentivice not doing this, and considering our current ruling parties, probably won't be either, but I consider this to be something that should be more talked about.