Don't get you epiphany. Who's the "white collar" in this case?
Cameras recorded the whole incident where the Patrons were seated. Nothing untoward there. My suspicious mind says that someone -and this could be the patron but I doubt it- has paid someone to substitute a platter of already prepared clean icec ream with one that's been... defiled, at the very last minute before the waiter picked it up. Who could that have been, I have no idea but someone of the staff would have to be in the know. I could fathom it better if it were of animal origin. I cannot believe it could possibly be human. Are there any cameras in the kitchen?