I've never approved of the hat mechanic. It's part of the uniform, not a piece of equipment. Indicating information by tossing/dropping an item is exactly the reason (among others) why beanbags were invented. I don't agree that using a different item, for distinguishing between receivers OOB and other events, is needed. Beanbags already carry numerous meanings, and coaches/fans/film understand this. But in truth, we needn't drop anything at all. The spot is never relevant. A mere hand signal would suffice. That's what we do when a pass is tipped, for instance. The "pass touched" hand signal indicates that an event has changed which rules apply. Likewise, a "receiver OOB" hand signal would accomplish the same thing.