I have had very mixed results with caches getting muggled. My Massabesic cache has been found at least 4 times by muggles and all of those left a complimentary note in the log, and some exchanged items. On the other hand, my Casco Bay cache disappeared three times before I gave up on the spot. I blame the disappearance of the caches partly on geocachers who didn't rehide the cache properly and/or were not discreet in the presence of the muggles who ultimately removed the cache. I don't mind replacing a cache, but it frustrates me to have lost the opportunity to read the log book.