I've also seen dedicated cell phone charging stations at other airports that have USB charging ports alone.

USB-only chargers in airports definitely exist, and are sometimes fought over in busier airports.

I believe there are more USB ports than generic power sockets.

In my experience, the USB ports are all in use at any gate with more than 10-15 people waiting at it.

Newer/remodeled hotels and airports are full of these things now. They don't exactly jump out at you, they would be easy enough to miss.

AFAIK these things are just dumb voltage sources, they don't have any USB controllers that could be hacked. At least, the ones you and I can buy don't. But there isn't, in principle, any reason why they couldn't have such controllers, either.