We’re a small corporation where everybody still knows everybody and our policy is that spouses are always welcome to come along as long as there is a seat available (meals included). It’s a small little perk that barely costs anything and is great for morale.
In reality, after the novelty wears off the privilege rarely gets used. My wife might come along once or twice a year. Between finding a baby-sitter, dog-sitter, not knowing how many company personal are coming and the fact that when we go on the road, we generally work, makes the privilege hard to use.