It is possible that they know but it would be a breach of legal ethics if they told Samsung. I would not bet on it being something they can't get a hold of, but if they are found with any evidence of doing so it would not be the easiest thing for Emmanuel to get out of. Any lawyer who breaches confidence of his client would be immediately disbarred. I am not sure what incentive HTC would have to tell Samsung either. They are competitors more than Apple and Samsung are because they both use Android. HTC would rather Samsung gets pulled down than Apple at this point. In fact, Apple is using Samsung's success to pit other Android producers against them. If Samsung does not pay any royalties then they have a pretty big advantage over the rest of the Android manufacturers. Even Google would rather have Samsung taken down a notch to keep control of Android in their hands.
Pass the popcorn, this is getting really interesting!