Happened to me. I was in the yard, doing X, wife went out to store, locked house, nobody home but the cat, and that cat hates me, so it wouldn't open the door. It was about 30 degrees out.

There is NO non-destructive way to get into my house, and, unfortunately in this case, there was no way for me to get in. I thought about it for a while and decided to keep working outside for a while, and if I needed to get in, I'd break a window (and set off the alarm...oy).

Fortunately, she came home within the hour, but after that, I hid a key outside - no it's not under a "rock like" thing or under the door mat. In fact, it's not even near the house at all. But it's there if I ever need it. Kids know where it is too.