I think you just opened a can of worms.
While I have stayed at some fabulous places it was never a mental option to take a robe. I guess, if it does not seem as though they intend for you to take an item, then you should not take it. That is where subjectivity come into play.
I have seen this discussion get aggressive previously. There is a reasonable argument to say that you are a common thief. Others will say, that it is deminimus.
Personally, I believe that a robe rises above deminimus.