About 3 months ago, we had a problem in some smaller accounts where they were getting core flavors (pepsi, dt pepsi, dew, dt dew) off of their grocery trucks at a ridiculously cheaper price. I heard they were in the process of tracking down which bottler sold all of this stuff to the vendor, but here's my question: why would Pepsi, or any other bottler for that matter, sell truckloads of their best selling products to a third party? I know it happens in the case of warehouse distribution, but if we knew they were going to be selling to accounts that already contract with Pepsi, why would they still go with it? There were a few instances where a couple accounts wanted me to pick them up, but I would refuse to do it. I'm not going to credit them out of my plants pocket for something we didn't sell!!

I'm no business major (obviously), but where is the benefit for the company?

I believe it is called transshipping. It does not sound like the bottler is involved but the vendor probably has area in multiple Pepsi distribution ownership areas. If one Pepsi Bottler is cheaper they are probably shipping it across county lines.