DEAR MISS MANNERS: Our granddaughter, who is 5 years old, came up to her grandfather, who was seated at the dinner table, and told him, “Get up! You can’t sit there! That’s my chair!” Our son and DIL were witnesses. I came into the room, found my husband standing at the breakfast bar, holding his plate and eating his dinner. I said, “For heaven’s sake, you can go and sit down!!!” He replied, “We’ll talk about this later.” My husband later told me that because our son and DIL were witnesses, he had no desire to say anything. “She’s their daughter, and we have no say in how they choose to raise …