next time u should say something or else u will never forget it for the rest of ur life..
yeah, that was my point. At the time I just talked myself out of it, I guess. I figured these Londoners know better than me, I'm a visitor here and never had to look out for abandoned bags on the subway in my city (back then).
I guess you worry too much about being embarrassed as a teenager. Now I will just say "Whose bag is that?" and if someone answers "Mine", then it's no big deal and everyone goes on with their day; you didn't really disrupt anything much. If no one answers, well then it's not just on your shoulders; now everyone in that subway car is aware of it and it becomes everyone's problem to do something about the bag.
Anyway that's why I was interested about this Baumann guy's experience. If a guy takes off his backpack and walks away immediately, that looks strange. If he takes it off, puts it down and stands watching the race (maybe his back is sore from wearing it all day), then after 10-15 minutes walks away without the bag -- then he might have honestly forgotten it. Most people would stop him and say 'hey, you forgot your bag' -- mostly to be nice and prevent him from losing his wallet, phone, etc (not because they think he's leaving behind a bomb). But if you stopped paying attention to him, you might not notice him leave, or you might forget that the bag on the ground was on his back and not the person next to him who's still standing next to it. So many people in the photos and videos of the scene wearing backpacks... like every fifth person.