Guess it depends on your plan/run frequency/ goals, etc. Ex: I only want to run 4 days max/week. But if I like the structure/content of a plan that has, e.g. 5 days, I will take one of the easy days and drop it/do cross training. So yes, I would count your hiking as cross training and call it the equivalent of an easy day. But I would do that because I’m in the “no race goals” stage of my running and so it works for me.
In the past, if “life” occurred, I would generally look at trying to reschedule, or if it wasn’t a recurring theme, just drop that easy run and not worry too much about it.