[bert]

I will argue that their space is mostly with out air.

[cgbg]

True and funny story:

Many years ago the wife and I were looking to rent a house in a small town.

The advertisement said “house for rent” so we visited to check out the place. It was an old but large house with a reasonable rent and we were seriously considering going for it.

But—before we left I realized we had not seen every nook and cranny of the place so I asked the landlord “what is behind that door”.

He responded “the other tenant”.

Oops.

So, think of the UFOs as the “other tenant” they forgot to mention in the ad. ;-)