I had exactly the same reaction to that interpretation as you did,
Justine.  I can't believe that MT was saying anything other than that
"you've got these freedoms, but you'd better be careful not to use
them because you'll get in trouble if you do."  i.e., pure sarcasm,
as you say!
(you can put red, white and blue lipstick on Mark Twain, but he's
still Mark Twain...to coin a phrase!)

Benjamin N. Wise
Keene State College