My work place has a day program in which we take a few people with disabilities and provide them with certain jobs they can do for a year, which provides the people at the top with a nice and humanitarian way to save money. The job is not really physical, so when we are lucky we can get people with physical disabilities who can function the same as full time staff members, but the organization providing the program is fully opt-in or opt-out and we don't have much room to pick people individually.
I manage the afternoon and night staff, and a big part of my job is resolving stupid drama and making sure everyone gets along and can work together as a team. It is fairly normal for people to leave things in the general hope of finding those things the next day, especially food. In the recent year I've gotten complaints of food items disappearing, couldn't really find out who is doing it and then people start accusing each other, which is bad for work, and frankly it kind of sucks going to work and finding out your lunch is gone.
Yesterday I found out the infamous food thief is. Unfortunately she is a mentally challenged person from the disabled program who kind of has the mind of a 10 years old, I scolded her, though the "don't take other people things" message didn't seem to sink in as 20 minutes later I had to stop her from doing it again. I am not sure what to do beyond that, I am trying to be sensitive to her special needs but I also need to be sensitive to the completely reasonable needs of everyone else in my staff.