Sign in a cake shop window

Ignoring the obvious grammatical error, this is a very odd thing for a cake shop to proclaim.  Surely a successful business model would be founded upon predicting that people entering the shop already wanted cake?  Stating baldly that they hadn't made any cakes because they didn't know a cake-wanting customer was going to arrive is naive at best, and fatal at worst.

It might explain why the shop was closed.

More deeply, I find the reference to the song disturbing.  I had to endure it on a 1950s triple-cd that a friend of mine bought in a service station in Kent, and then played incessantly during a continental road-trip.  It is twee and awful and lyrically baffling.  To be reminded of its existence is not a good thing.