Sure, it's fantastic if, for example, you were at the Ariane Grande concert or it you spend a lot of time in the vicinity of London Bridge and there was a real chance you might have got caught up in the terror attacks and people would genuinely worry. But I feel like people obsessively marking themselves safe just because they live within 20 miles of the event when there was practically no chance they were involved just feeds the general hysteria and makes people feel that no one is safe.
To be honest, I was not beside myself worrying if my friend in leafy south-west London who probably crosses London Bridge twice a year was safe. What happened is horrendous, but 6 people died. Practically everyone in London is safe. I feel like people's need to mark themselves safe is increasing the impact of these attacks when we should be trying to do the opposite.