Product review (3 stars): Yeah, it works. And it didn't cost too much either, but you can make one if need be.
It works. However, if you are really stuck for such an interlock switch, it is not hard to make one out of a limit switch as used in microwave oven doors, or anything limit switch that's used in industrial safety interlocks. Especially, if you have one with a cat whisker on it, that will work as well. When you think about it, it is just a modified M-O-M Push Button.