Corrected entry: In the scenes 4 years after Chuck has been on the island, we see he has grown his hair out and his beard is very long. What is out of place is his mustache is remarkably well-groomed. Whiskers don't grow evenly, and unless he had some scissors or something else to trim with, it's very unlikely that his mustache would be so evenly distributed around his mouth.
Rooster of Doom
25th Mar 2003
Correction: Actually, anyone with a mustache can tell you that it's no great feat to keep those reasonably well trimmed just by biting the ends off - and you would, unless you like them trailing in your mouth all the time.
Rooster of Doom