I don't think you should fall asleep at a party shoes on or off, if you're asking about taking a nap that is. If you tired stay home and rest. If however your talking about being passed out drunk, I doubt seriously if at the time of your collapse you'll be thinking "Should I remove my shoes before hitting the kitchen floor." And I doubt seriously if people the next day will be saying "I can't believe he/she left their shoes on."
Passing out with your shoes on shows that you were so drunk you did not go to bed, but instead you passed out. Having your shoes on gives everyone else at the party permission to mess with you while you are passed out. Some people can get pretty mean too. Good luck and be safe.
Someone might tie your shies together, then when you get up you will fall. Not only would this hurt & be an embarrassment issue but you have the potential of breaking bones or other damage (say you fell into coffee table, concussion)