A few Sundays ago I took my car to a do-it-yourself coin-operated car-wash (1 CHF for 2 min or so with the pressurized water gun). I put my 2 CHF in, but it kept returning the money to me. Thinking this one was defective, I went to the next stall, and the same thing happened. Then I looked at the machine closer, and saw it's "
Hours of Operation" states that
the machine only works weekdays 09:00-19:00 and if off on Sundays
Why??

Does the machine need Sundays off to go walk in the woods with other machines?

...but really, what could be the reason? I thought maybe noise, but this machine in in an industrial park next to a main railway track, and no houses near it really. Are all the coin-operated car washes closed in CH on Sundays? I never really noticed this before....