"Nothing seems to have been taken or tampered with but how would I ever REALLY know? "

You would know something was taken if you had brought it to the hotel and it was no longer there! Same as tampered with--if it is different than you left it--but as said, housekeeping is sometimes notorious for "straightening " up and moving what is left on a dresser or desk. I always tell them not to touch. I put stuff where I want it, I don't care where THEY want it.