Well that bites, you were definatly in the right ! but....
Maybe you could have dealt with the kid better,
you said he did apologize.After all he didn't know better when his dad tells him it's all right,It was the dadthat got him in trouble.
At 12 or so are you going to tell your dad you don't think it's right to use someones stand or not, if he tells you to.
Maybe if you said to him that "it's not right to use other peoples things
without permission no matter what your dad say's."
then tell him it's not his fault his dad should know better!!

This might have made a better impression on the kid,while teaching him a valuble lesson his lame father should have done already!
After all children only learn what they are taught.