I went to Borough market a few weeks after the attack because I was disgusted I'd never been there before. I used to commute through London regularly and had never heard of the place. I had the normal 'are you mad?' concerns. I've been going to potential terrorist spots my whole life, I'm not going to stop now. You use a bit of savvy and stay awake in potential hotspots.
It's probably fairly safe if you keep away from drink, drugs and prostitution. And you don't get wound up/violent easily, or tend to make others wound up/violent.
50p each way on the bus to people-watch through the hotel zone (once is enough, but note the turquoise ocean). Then back to sanity at my favourite centro restaurant. Four courses and a drink £3 :) Viva (the real) Mexico!
All police out here is armed. And they petrol the hotel zone as a lot of the income comes from torrists to make people feel safe. They are more like check points than petrols, your Taking my words out of context. Anywhere you go in the world has crime.
I can highly recommend the Rui yucatan it is brilliant, safe and a gated community absolutely class holiday!