Here is a great blog by cairngormwanderer on the (ab)use by some of facilities provided in remote areas. Kirsty and I camped outside this bothy in 2012 and we met a couple of the guys who look after it then. It isn’t always a pleasant task and it’s b****y miles to carry rubbish out to the road head.
http://cairngormwanderer.wordpress.com/2014/08/25/a-disgrace-and-a-challenge-to-youth-groups/