I think China erred by sending such a large balloon that was visible to the naked eye, causing the American public to demand it be shot down. There's no hard rule about where national airspace ends and space begins.. a lot of times they fly too high for planes to reach, and under certain circumstances balloons are allowed through national airspace.. so if the balloon isn't causing a problem (like being a hazard to ai…
What does that have to do with the price of tea in China? There's no hard rule about when life begins but killing a 5 year old isn't a 22nd trimester abortion, it's murder. 18-60'000 feet is class A, controlled airspace in the US and Canada.
When the US sent U2s over the USSR, the rationale wasn't that 70,000 feet was "space", it was that it was that 70,000 feet was too high for soviet radars detect and and soviet planes to intercept.