I really don't get this line of reasoning. If I do something with a product that is (maybe even explicitly) unsupported by the manufacturer I don't have a reasonable leg to stand on.
We've recently had this with a customer where they used the concrete calls of our app to automate some of their stuff (we had had no public API for that action at that point because we hadn't had the need so far and so did no other customer or to be precise: no customer was prepared to shell out the cash for us to develop it) and after we changed something they suddenly weren't able to script the creation of customer entries in their installation. We had told them at least two years ago that the way they interacted with our system was but supported (we only noticed them automating stuff back then because it was throwing exceptions in our backend) and while we were nice enough to fix it this time because the fix was trivial we recommended that they should switch to our supported API. Two weeks ago theyir stuff broke again and we told them to use the API or fuck off.
NDAs, etc. are contract law. Contracts need to be entered in without duress as they would be felonies otherwise. The others are societal contracts which operate much more akin to taxes from a philosophical point of view. But calling today's copyright law a temporary restriction is cynical at best.