Well, the pipes are not frozen now, after all it is summer in the city and it is as hot as a fourth of July firecracker. However, especially on some newer houses, I am just now finding outside faucets (even the frost free variety) that ruptured due to freezing this past hard winter. A frost free hose bibb looks about the same but internally has a long valve that actually shuts the water off inside the structure (warmer location) and the excess water drains outside. So the hose bibb, exposed portion, retains no water. EXCEPT, that does not happen if a hose is left in place at the faucet. Often the hose will lead to water being retained inside the faucet -- frost free or not it cannot drain. What happens then....... well, in cold weather they freeze and break. The good new is that, at least with a frost free hose bibb, normally they burst on the exterior side of the valve, so they do shutoff but they leak when the water is turned on. A first clue, to a home inspector that this is going on, is when there is almost no water pressure at the hose bibb. That is because it is leaking profusely inside the crawl space. Sometimes you hear it and other times you will see it leaking out around the hose bibb or the siding. The risks of broken pipes are even greater with an old-fashioned, not a frost free, outside faucet. Leave a hose on those and you have the same problem except, when it thaws, you are likely to have an ongoing leak, valve on or not. Bottom line: In winter take hoses off the exterior faucets. The photo below is the problem described, only at a new house.