Neighborhood watch

My upstairs neighbors are moving to Switzerland. The question is, have they already moved to Switzerland? And the answer is, I really couldn't say. Hmmm. Surely I ought to know. There are only four apartments in the building and what these particular people call their floor, I call my ceiling. Is it actually possible for them to have moved out of the country without my noticing? Would there not have been some "schlepping all of our possessions down and uncarpeted staircase" noise? True, I haven't heard their cat lately (hooray!). You know what? I think they may really be gone.

I fully intended to say goodbye.