Welcome to Shit People Steal, in which we ask restaurateurs what items in their restaurant have been (or are frequently) stolen.
Perhaps the best sort of Shit People Steal story is one in which the restaurant enjoys some sort of retribution for patrons' bad behavior. Consider the case of Mobile, Alabama fine dining restaurant True, where chef Wesley True stocks the bathroom with posh Niven Morgan soap:
People steal our fancy soap. Once there were a group of diners at the restaurant that were mainly 30-something women. One of them went to the bathroom right after my wife, who is the sommelier, went in to do a bathroom check. A little later my wife went in again, and noticed the soap was gone. She went to the women's table to fill up glasses and they were all whispering and laughing. She didn't want to accuse them of stealing, even though we knew it was them, so we just charged them for it. We added a "misc." charge of $12.95 to the bill, and they didn't say anything about it.
Also, people used to get pissed that we do not have salt and pepper shakers on the table. That's because 30 percent of my customers would add salt to their food before tasting it, then send it back and say it was salty. So we put some nice metal petite shakers on the table with big grains of kosher salt in them. They would give them the illusion of salting the food except no actual salt would come out. And, by the way, people started to steal these.