Eh, as long as my employers don't care (they don't), I don't care. I have no illusions that my code/our code will give Microsoft any valuable training data it couldn't trivially get elsewhere.
In theory there are no rules about importing code, beyond the usual licensing issues. But people use SO and such all of the time, right? If one *really* wanted to do a global audit of improperly imported code, we'd all have bigger problems. So from that perspective it's status quo.
But I don't want to be the person caught uploading proprietary code to another company's servers.
It's not a major issue, and I doubt it'd ever be a practical problem. But fear of punishment keeps me away.