I used to think it was people who meant to collect it later and lost an occasional one, but there seems to be an epidemic of leaving poo in pags. Surely lifting the poo up in the bag is the unpleasant part (warm, squishy and smelly). After that, why not just take it to a bin? Keep a spare carrier bag in a rucksack for transport if you want your hands free. Obviously leaving poo lying around in bags is unreasonable and dog poo just left behind would biodegrade quicker, particularly in the park, so surely it's better to just leave the poo than bag it and leave the bag? Does anybody understand the motivations behind leaving the poo in bags?