No, under Open Skies the flights are over the national territory. This is not the same as non-negoitated probing flights along the border over international waters. These happen regularly.

Yeah, except it is not clear this in fact was "over international waters". The U.S. says it was, the Iranians say the drone crossed into their airspace. Now I know many take the U.S. word for it, but given the escalating rhetoric, given Iraq, given people like John Bolton are in the administration, I wouldn't.

Moreover, as I said, the U.S. knows Russia is not about to conduct a surprise bombing raid on them, so does Russia know the same of the U.S. - They both have nuclear weapons and doing so would be catastrophic for both sides. Iran on the other hand expects a U.S. bombing raid any moment and in fact Trump just admitted one was ready to go ahead, so it's a bit different.

In fact, I suspect the U.S. knows all this and provoking a reaction from the Iranians to support further action from the U.S. was precisely the goal of this drone.

I don't think "US knows it" is how border safety works. Either way I fail to see your point how that would be different with China.

As to motives, who knows. Iran could be trying to move confrontation from economic to military, where it has a shot on regional parity. With all talk about Bolton, Iraq, Vietnam and on this admin is very docile. Iran came out on top from this confrontation, bolstering its regional influence, so why not.

Iran has zero ability to win a regional war against the US, unless you consider bombing Israel to be critical damage to the US, or if the US has no stomt for Iranian casualties.