Yes, your clothes could send you to jail. It may sound like Law & Order: The Jetsons, but there's no real reason this kind of data can't be admissible in court. In fact, it's already happening. A woman in Pennsylvania called 911 and claimed that a home invader raped her, but her Fitbit contradicted her story (she was awake and walking around when she said she was fast asleep). Her own fitness watch helped prove that she'd pulled the whole story out of her ... you know, and now she's facing misdemeanor charges.
So wearable tech can help bring criminals to justice. That's good, right? Well, here's where it gets fishy. There are already "alibi apps" -- programs that covertly record all your interactions and surroundings to prove you weren't (for example) holding a chandelier in the study when Colonel Mustard got whacked. Sounds innocent enough, until you remember that there's a term for people who intentionally go around establishing alibis: "guilty as fuck." Using this app is a little bit like going up to a cop and saying, "By the way, I'll be at the movies this afternoon when my wife gets murdered."
The idea that people are already thinking ahead to use their trackers as alibis means that these things will have all sorts of clusterfuck legal potential. What happens when someone pays a hobo to hold their smartphone (or straps it to a dog) while they go out and do crimes? Or what if someone borrows your Fitbit to incriminate you? These things will happen at some point. Hey, maybe that's why everyone becomes a couch potato in WALL-E. In the future, being fit won't be worth the hassle.