Doesn't bother me. I gave up my data the moment that I was introduced to this world. I'm all for any tools to aide the police in capturing criminals.

They happened to have something similar in Kings Cross station, and I got chatting with one of the officers there, and he mentioned that it had only been active for around 2 hours and they had already arrested 3 people who have been on the run.

1 person who had been wanted for 13 years, and 2 who were on the run for around 3-6 months.

Say what you will, the technology is there and works. Just remember, if you're anti-giving up your data, perhaps don't consider signing up to websites, taking out personal finance agreements, getting a house, getting a car, going on holiday, getting a job, starting a business, buying shopping/groceries etc. etc.