Better than having no reason at all as to why they couldn't see them.
So your saying that because they were in the same room is enough reason while I'm saying its not. You said, I said... that's pretty much what it comes down to.
Now Ilbranteloth has given a very good explanation about why he feels that the ranger NOT being able to see the items in question. What again was your reason that the ranger COULD see the items? They were in the same room?