I'm still testing this, and it's one of the weirdest things I have ever seen, but I think that my Apple Watch is locking my girlfriend's 2011 15" MacBook Pro. It started last weekend when her battery suddenly expanded, and bent the bottom cover. I took it into the Apple Store and they replaced the battery and cover, to the tune of $287. We brought it home last night, and I was checking it out. The video was acting strange and had some really weird artifacts all over the screen. This was behavior it was not exhibiting before the repairs. I was going to take it back today and have them fix what they broke. But before doing so I decided to see if I could avoid another Genius bar appointment, and her being without her laptop for another 4-5 days. I thought I'd just crack it open and make sure that they just didn't leave a loose display connector (I think they tightened the display hinges while they had it). I opened it up, and the display cable didn't appear askew. But I pulled it off, and re-seated it anyway. Voila! The display started working fine. But then the mystery started. I had the laptop on my desk at work all day, so I could watch it to make sure the display was behaving. Several times in the first few minutes of using the machine I noticed that the screen would just lock, even though I was actively using the machine. I checked all of the power settings, and everything looked right. However throughout the day the behavior continued to occur. I couldn't figure it out until a few minutes ago. It's my Apple Watch! Every time my left wrist slides by the headphone and microphone jack on the left side of the computer the screen goes dark and locks. When I pull my arm away the screen comes back on and the password prompt is up. If I take my watch off and do it I can't reproduce the issue. Really, really weird.