Not the first time it's happened, won't be the last. We intercept aircraft from Russia all the time as well, and if China sent some near our borders we would intercept that as well. We simply don't do it in so dangerous a fashion. Anymore. I did hear about this one time 30 years ago where one of our Tomcats intercepted a few of those new (at the time) MIG-28s, and one of them actually flew just a couple of feet above the MIG, INVERTED, in a negative 4 G dive no less, when the MIG locked up his wingman. I think there's even a picture of the MIG pilot taken by the RIO while they we're doing it that's floating around somewhere. Or so I heard.....