Week 2 Learning Log: Bad Design

As I read the "Design of Everyday Things" it mentioned a projector design that was flawed. I immediately remembered an event that had happened earlier in the week in one of my other classes; Human adaptability. The teacher was showing a very old film on an old projector - We should have seen what was later to happen coming from a mile away. First the projector had to be loaded up with the real by a film tech - not a task that any laymen could accomplish. As the film played it made its usual noisy clicking sound that most projector make. Everything was going fine - but as the reel was three quarters of the way through playing - the empty real that the film wound into was filling up fast - soon the film was overlaping the new reel that it was unloading into - it seemed to be shifting out of line with the rest of the film - but the movie played on with no problem - As the reel finally ran out, the last frame came out of the reel and proceded to unravel - film all over the place - on the floor! - This is a prime example of bad design - way could there have been some mechenism that could stop this from happening? I don't have any idea! The user and even an expert did not anticipate this from happening. I am sure that some projectors have a fail safe that could prevent this from happening, but not in this case!