Even explicitly knowing I was looking at signs telling me to "relax and enjoy myself," I found myself interpreting the sign as the warning/restriction counterpart message until my second or third (even more careful) reading.
It's a lot like the phenomenon where if you include and and twice in a row, you'll likely not realize the typo.
It's a lot like the phenomenon where if you include and and twice in a row, you'll likely not realize the typo.