I remember, back in my semi-auto days, when I'd buy a case of Marbalizers every weekend. We've got a pretty trustworthy group so I didn't think twice about going inside for a minute while leaving my paint on the table. Long story short I came back outside and I found a $5 bill in place of where a bag of paint was and saw a kid walking back to his table with a bag of paint. I asked why he took it out of my box and his response was simple
"Well, consider it a profit for you."