Luckily, husband absolutely understands and never digs in before Dad and never grabs the last bite when we're visiting. Of course my BILs are all young enough to be my husband's kids, and most wouldn't know manners if they were hit in the face with them. I don't know ... a little thing called respect.
Respect, it's what we learned growing up...you and I both grew up in the military and I think that has a lot to do with it.