hm, i looked up the def. for 'muck'
1. (n) The area on the table where all of the dead cards are placed. Any hand that was folded and all burned cards are placed in the muck.
2. (v) To throw your hand away into the muck. This term is often used when another hand is shown at the showdown that beats your hand.
so technically, you can 'muck' your hand. he doesnt have a right to see them.
http://www.pokertips.org/glossarydefs/43.php