LOL...please don't take this the wrong way. Just a genuine question...does your grandmother do anything different than anyone else...like "older people" stuff (like carry a cane, limp, shake, talk particularly loud)? It is more than likely the way she entered the house. Did everyone get excited when your grandmother came over (like yelling "hey grandma!" or hurry over to hug her)? I've just known dogs to get a little confused or uneasy when someone acts or does something different than the people he is used to. Maybe your grandmother is totally not a "little old lady"...lol! Just a thought.
