Hummm, sounds like your place is the "underground railroad" for lost dogs, aka Peachdogi Hotel
In all seriousness, I am so very sorry for the unsettling event. That would have freaked me out as well. Did the dog belong to the man who stopped? If so all's well that ends well.
I just can't imagine just "losing" a furkid.... I mean unfortunately the grim reaper will occasionally pluck one from your loving arms, but LOSING one? Give me a break!!