When someone is not there, you'll start to think where he is. That's if you know the person. If you don't, you propably won't bother. Why would you? Most of the inhabitants of this planet are just numbers. And these numbers are too big to comprehend.
But let's say you live in the neighbourhood and you've seen me before. Walking my cat or shaping sculptures of snow. Then you would pay a little bit attention, and maybe ask, where is the guy? Perhaps on vacation or something. Or moved out. No wonder the truck wasn't noticed, since there's so much work.
And so it goes.