I think the snack basket etiquette is 1 or 2 items per pass through the cabin. Seems like the snack basket (a relic of US Airways more than AA, right?) is used on the E175's and similar. Shortish flights with 10-12 people in F. They're probably stocked to handle a couple passes of the snack basket, enough where someone eating 3-4 items is no big deal, but not enough that everybody gets 5 to take home.

I've never encountered anything in a snack basket that I desperately wanted to take off the plane and eat later. We're talking about little bitty bags of nuts or chips here...