Yeah, karma don't exist....neither does your responsibility to make good a mistake made by the company who erroneously shipped the product to you...
What if someone noticed that a marijuana grow product was shipped to you, or was at your doorstep? Could be bad for you...
Or what if someone notices that a marijuana grow product is being shipped by you back to the distributor? Could be bad for you...
The point is that your obcessive-compulsive need to ship the unsolicited product back to the distributor could do you much more harm than good...
Their bad, not yours...don't make things possibly worse by participating...