Sensor is in valve stem, not cap.

Why are you worried about someone draining the air out of your tires? I've never heard of anyone doing such a thing. Is it that or are you worried someone might take them?

Don't you think that will be somewhat annoying trying to fill up the air in your tires. You now need to find that little key thing to unlock your valve stem caps?

They look nice but just seems a bit annoying.