I hear you on this one. We have a window seat going to the second story, and the new pup will basically sit guard there, and if anyone comes by, mailman, paperboy,other cat, dog... she will "alarm" us that someone is coming.
The second bold is very true. My old pup would stand guard by my dad, and i would jokingly hit him, he would say ow and yell help, and he would try to protect him by geting between me and him and barking at me. The new pup,she is also very protective, sleeps in front of the stairs as to protect us from intruders.