I think that the issue is exactly as you said... non-random. It is one thing to build in a system of triggers where "if this, then this" is the basis for determining what happens. A random encounter table might be infinitely harder to implement. Would you like to have your odds of being attacked in the middle of the night be the same s your odds of critically failing a roll currently are without the loaded dice option? Because I have a distinct feeling that that is what you'd get.
I would prefer that over not being able to rest in that area, it gives me the choice instead of being a restriction. Also this is what I think they will do not what I want them to do, which is the main goal of this thread. I very much believe a more complex resting system will be introduced when Inn's are.