My experience is with making a few consumer electronics products and running through the UL/CE gauntlet. In those cases, the ‘materiel’ required to make sure you don’t shock your users to death is a bigger lift than what happens if one of nine I/O lines are held high or low or fuzzed in interesting ways when there are secondary layers of fusing built in.

From what I recall your background was in industrial machines and I concede the point that if sent an inappropriate signal, disaster would ensue. I don’t connect my CNC machines to my network but I meant to scope this discussion to home goods which are meant to have a lot of protections built in - specifically against the “user” - which compared to “internet” or “electricity” will always trump unpredictableness :-)