No doubt about the owner. I was surprised and happy too when I saw the car had a Polish plate. I didn't know this upside-down house business was international.
I saw these houses in some other cities on the Polish coast and in Zakopane (where I spotted this Panda https://platesmania.com/pl/foto20022809) so it seems to be a bigger enterprise than we thought
That's amazing, and apparently, based on my experience and seeing the loudspeakers on the Panda too, part of their advertising is to drive around and blast loud music to draw everyone's attention.