Surely this depends a lot on where in the world you are? I regularly break the speed limit while overtaking police cars in the UK and have never been pulled over (but never by much - I figure there's too much work involved to give me a ticket for only going 5 miles an hour over the limit). In fact, I've unintentionally overtaken police while going over the limit in Qatar and the US as well without being pulled over - both places where I'm more fearful of the police than when in the UK.