and since we expect them to be quite extensive, it's very unlikely he never triggered one.

I do not expect this. Time-tuners are fine. Invisibility cloaks are fine. Draco's torture hex was fine. The only thing I can think of that Harry did that might have triggered a ward without permissions was bring in the transfigured unicorn. And that isn't conclusive at all. It was transfigured, and as far as I know the Defense Professor can't just bring magical creatures in to Hogwarts either.

I don't think it's been tested.