There is not a penalty, per se. They are not allowed in the restricted area, so a passenger having an item that is prohibited has a number of options: they can put it in their checked luggage, they can give it to a friend or a greeter who is with them, they can mail it back to themselves, or they can surrender it at the checkpoint. The only rule is that they may not enter the restricted area with that item in their possession.
On February 15th, 2011. See this statement in context.