If you were disabled, and every step you took was both painful and exhausting, you would be trying to save your dwindling energy reserves to get through the shop, the check out queue and back to your car in the car park.
The notion that a person who finds every step agonising and exhausting would be able to traipse all the way back to the trolley bay to pick up a replacement trolley (or even be able to walk that far without her stick) shows a sublime ignorance of what it means to be disabled.
I'm actually quite shocked by the casual cruelty of some of the comments on this thread. The IKEA stores themselves show no consideration towards people with walking difficulties (keeping their short cuts through the labyrinth secret to force everyone to take the long way round), and I personally am no longer able to visit IKEA, because I can't stand up for long enough, or walk far enough to survive the experience.
However, back when I was still just barely managing to drag myself around I remember how relieved I was to have a trolley to lean on, allowing me to take more weight off my painful leg. The thought that I might leave it outside the disabled toilet with my walking stick inside, and come out to find it gone is horrific.
I probably wouldn't have been able to walk far or fast enough to catch up with the trolley & stick thief, and would have ended up collapsing to the ground and being unable to stand up again. If and when I did catch up with them and they snarled at me and shoved the trolley into me when I asked for it back I would probably have had to leave the store and spend the next couple of days in bed recovering.
Maybe it makes me a nasty evil person, but if I was the resident Deity of IKEA I would ensure that everyone who would defend stealing a disabled person's walking aid should suffer at least a month of the exquisite agony of having to walk when every single step is a symphony of at least 5 different stabbing, wrenching, burning pains. Teaching them the miserable art of carefully mapping the shortest distance between two points, and hoarding every last scrap of strength, dreading any unforeseen obstacles that would be enough to leave them stranded, in a state of collapse and unable to get home. If it teaches them a tiny bit of empathy that would be a plus, but as a vengeful deity I'd also enjoy torturing them.