Don't many problems but there are always a few nutters about that are out to cause problems. Or are they just out to cause problems? We have a local MUP that runs through the town and is a favourite haunt for the "Youth" of the area. They have a few choice spots where they congregate and it is under the bridgs that go over the MUP. Whether they realise it or not-The fires they light in the path and the beer bottles they leave around are going to cause problems. In the words of the local Authorities---They have to go somewhere and it is better they do it out of the public view rather than in the town.
The mere fact that they ruin the MUP with the broken glass- the rubbish they leave and the damage to the path seems to be secondary. And I have to agree- I don't want them acting the way they do in the town but I would prefer it if they act in the correct manner wherever they are.