[em500]

Because in practice people don't clean up after themselves, especially in public places.

[vidarh]

In practice people are pretty good at it when you create a culture where it is ingrained. Not sure about Sweden, but in Norway how to handle the freedom to roam is taught from primary school on, and while the camping is legal, not tidying up isn't.

[JR1427]

The majority do clean up, but of course this goes unnoticed.