It's important to have privacy from your significant other's parents. It shouldn't have to come to trickery and shenanigans in order to catch a grown adult in a lie, but some people apparently have no goddamn rules, so things like this happen. Mom went and revealed that her emergency key didn't work, then had a full-on adult meltdown when she was caught in her lie. For some more mother-in-law wildness, here's the one who forcefully grabbed a grand-baby, then demanded an apology.