One of my first shops in a new location (a new town I had moved to), I overheard the two employees having a personal conversation behind the counter, while I waited for service, standing at the counter. That went into my report. The employees disputed the report saying that I had lied. The employees claimed it wasn't them or that I was flat out lying, that they were talking about "work."
In my report, I had carefully described both employees and detailed their personal conversation, almost verbatim. The MSC came back to me and told me that the employees were disputing it. I told the MSC that I went above and beyond and provided MUCH more narrative that required for a report. Why go to all that trouble to make something up? And if the store owner was still having doubts, the store owner could review the security tape. I had made a point of looking right at it during the visit and described the location of the camera.
I was paid, but told that I could no longer go back to the location, for obvious reasons.
Same town, my boss was shopped. Her first reaction was to dispute the report (she got like a 67% on it.) I said let's go over it. We went over each point and I asked if there was any possibility that the shopper saw it like that. I told her to pretend she was a customer with me. After going through the motions of the customer, from browsing to checking out, with a heavy sigh, she conceded that, "Yeah, that was the customer's experience and the report was probably accurate."
The experience was good for both of us. I learned who shopped them, I was able to see if from a customer's perspective, and it helped me be a better employee while I worked there. And for those who want to ask, no I don't shop for THAT MSC. I'd like to...especially since that company [that I worked for] went out of business years ago!
Sometimes the companies listen, sometimes not.
And I think often, employees have a knee jerk reaction to dispute part or all of a report.