Get a friend.
Get a fancy dress costume, one Policeman and one Criminal (Or just dress like a robber or summin)
Have the person in the Criminal costume handcuffed (With toy handcuffs)
Walk with him (Dressed as the Policeofficer) to the counter and order for both of you, making sure you ask your partner politely what they want.
Be served and go sit down.
Have the Criminal friend complain he can't eat with handcuffed hands, so you unlock them for him.
Have the Criminal finish his meal and then try to run away, preferably try hiding in the Kids Area (If your McDonalds has one).
Try to slide across peoples tables and stuff.
Have fun.
Also, it's probably a good idea to leave before a real policeman shows up.