I did a mystery shop for a manufacturer that is trying to sell their product to a certain retailer last year and they didn't have any product in the store that was competing at the time. It was a well paying shop from a great MSC and I had nothing to report to them at the time and was paid quite well.
I shop this retailer both as a customer and as a shopper and this week they have a competitors product on the shelf as a "special buy" this week. I get the weekly sales email from them and thought there might be some interest still.
I went into my sent box and found the email from last year and emailed the MSC Director of Operations the fact that there is a competing product in that companies store this week. She likely called the company that is trying to get product placed and less than 30 minutes later I had an email from a scheduler asking me if I wanted to do this same shop from last year. I replied with the location of my choosing and got the assignment.
It never hurts to remember a shop from the past and know what an MSC's client is looking for.
I basically created my own shop. I just hope they have the product in stock when I get there today as sometimes it will not ship to all locations, arrive late, or just not show up.