I had a bulkhead row on a Super 80 and boarded fairly early on only to mind no possible place to put my very small carry on bag. Bin hogs in my own class of service + a selection of people boarding coach who crammed their stuff into the front cabin bins as they trooped along.
To avoid this board as early as possible and throw yourself on the bin you wish to use to protect it from poachers.
The FA's on American do not protect the front cabin bins! They turn a blind eye to the situation.