Wow this is great actually. In my country, robbing and snatching during late at night are common especially if your riding public transport and that's how dangerous it is. Some users might be checking their phone to see what's new or pop up on the forum but with this, maybe it would be avoided such using phones in dangerous places.
You should absolutely not be checking your phone in a dangerous place simply to see who merited you on the forum or who mentioned you in a reply. That's a little too much. Also wearing a smart band might give an indication of wealth which would also attract hoodlums.
It can also give your involvement in bitcointalk away and someone could trace your identity to the forum.
I'd rather wait until I have enough free time to check up the forum and catch up with whatever I had missed.