At first, I thought it was just me. That was until another friend of ours came in a bit after my arrival and got the same treatment. Same happy greeting, tail wagging, loving dog until about 2 minutes in. Then the "get out of my house" serenade.
After the guests have come in and the howling has subsided, usually someone in the family will mumble, "It's a little late, Daisy." They think she's just slow.
I think she's just hopeful that everyone coming to visit is there to visit her. Once the petting and attention we pay to her end with the greeting, it is then that we are no longer useful to her. We serve no other purpose than to take her family's love and attention away. She doesn't know it's ever going to end. So, it's obviously time for the guest to leave. Thus the barking/howling/crying.
This dog has been severely underestimated.