They are usually to big for that. But if you want them to nobody's going to arrest you for it.
This is a very tiny "Service Dog" and his head is even with the table top. The other people at the dinner didn't want to share their dinner space with the dog. The jury is still out on whether it is actually a "Service Dog" but that's a different issue all together. We can't insist on proof.
I haven't been able to get a clear picture of where the law actually lies on this one since so many of the "Service Animals" are larger and would normally be lying on the floor at the person's feet during the meal.
If it were a real service dog you would think the person would know how to treat it. They may use it for therapy and call it a service dog.