That is quite a story and adventure you had in Spain! However, do you believe what the owners told you was correct or simply believed in what they said? Either way, I am glad you made it back to the place you were staying regardless of what the dogs intentions at the time were.
Sometimes we do exactly that, I agree. Other times it could potentially be the exact opposite
I'm not sure, though I am inclined to believe what they say. We aren't any other animal but humans, so we've no way of knowing why any animal would do what they do. "Natural" behaviour can be anything from innate response to external stimulus or a learned response based on some past events. A human being can respond in some way to a certain stimulus, say, get worried when a loved one isn't home by night. An animal may or may not respond in the same way. After all, in the animal world anyone can get eaten anytime and they have no time to sit up and wait...