Whilst that is true, I'm more likely to get caught up in a terrorist attach in London if I go to London than if I don't
It would never stop be going, but I find it hard to believe anyone would be able to go without the thought entering their mind.
Just to play devils advocate, more people have died in train derailments in London in the last 12 months than they have in terrorist attacks. And there has been ~ 2000 deaths or casualties from traffic accidents in the last 12 months in London.
I understand your point, but you have to take a wider view of things too.