It has nothing to do with going out of business or losing money its about destroying product and forcing somebody to clean it up for his stupidity and it may cause other customers who aren't in on the prank to actually slip on whatever it is they spilled.
After working in a supermarket you begin to realize its the customers that can make that job pretty chity
Oh please some dude has to grab a mop for 2 mins and clean it up...big deal. It's funny and if it was me who had to clean it up I wouldn't mind because like I and many others said it was funny.