One of my pet peeves is folks that bring too much on board, and are not stopped. As we've all seen it results too often in others having to do the under the seat thing or forced to check lap top bags. I also do my best to travel light. I have long legs and need every bit of leg room available. Many airlines in Europe very strictly monitor size, weight and number of pieces brought on board.

It is worth a letter to Delta. Written as a request that onboard baggage rules be enforced. Nothing DYKWIA or whiney about that.

Sincere kudos to OP for giving up his F for military.