This question originally appeared on Quora. 
By Peter Baskerville, Founder of 20 Cafes and Food Businesses
I haven't heard of it specifically, but I can put forward a theory as to why a big-ticket retail business might advertise this fact - to help minimize or prevent internal employee theft.
Shrinkage (unexplained loss of goods) is a big problem for retailers. It averages in the US at about 2% of sales, which equates to over $500,000,000 per year in losses. Also, this 2% comes straight off the bottom line (net profit) which is only about 8-10% of sales for even the most profitable of retail businesses. So shrinkage is very significant and equivalent to about 20% of a retail business' net profit.
Now while shrinkage can come from various avenues like consumer shoplifting, vendor fraud and administrative errors, it is estimated that internal employee theft is the biggest cause of shrinkage. One easy way for employees to steal from a retail employer is to take money in exchange for goods sold, but then not process the transaction through the business' cash register or receipt book. The customer doesn't care about the receipt because they now have rights to the goods but the business does not get the financial benefit from the sale.
It is near impossible for management to pinpoint this theft unless they witnessed it directly, and even then an experienced employee knows how to hide the evidence (keeps the money in the till anyway) until there is a quiet moment where the money can be shifted to the employee's pocket without anyone noticing. This loss is only discovered at the half yearly stocktake, and it is impossible then to attribute the loss to a particular employee.
So retailers who advertise the fact that a customer can get $5 if a receipt is not offered or issued, is a form of crowd-surveillance. Because every reported case is quite possibly a report identifying employee theft. Either way, it is quite clever to have the sign like this at the register not for the customer's sake, but to remind the employee that their clever theft scheme may well be reported after the sale is made - so providing a good reason why they shouldn't even try.