It's certainly unexpected by the general public.
Of course, elementary school science is enough to figure out that if you bought a jar of apple juice from the store, replaced some of the contents with hot goat urine and shook it up before fully closing the lid again, as the air inside cooled it would pull the clicker back down. And you could return it to the store.
But if I read an article about mysterious tampering with "unopened" products in local grocery stores, I hope the police (and particularly, food packaging or food security experts) wouldn't be so baffled about it when discussing it with reporters.