I had an abnormal heart rate buzz go off for the first time. I was crouching/standing in my airplane seat waiting for people to get off for a good while, and of course to do so your body has to flex a bit (like a static isometric hold exercise) which can make heart rate go up. But I'm sure the device interpreted me as being at rest. Freaked me out and then I sat down and it went away. Triggered my fight or flight for a moment and I'm sure everyone around me must have been like WTF.
Still would have liked to see the progression afterwards on the stress and HR charts. Please add an alert symbol or something.
I'd probably be more worried if it went off while I was relaxing on the plane of course, not when I was about to take action, but it's still interesting to see so I can respect my body next time.