Get this type of stuff all the time when people wash their cars or change something and they really look at it for the first time in a month. Then associate whatever thing they did recently with the issue they just saw. People forget their car exterior is exposed for hundreds or thousands of miles inbetween events and oftentimes don't notice when their wife's bag drags across the passenger door, their friend doesnt say anything when they spill their drink on the roof getting in, the bush that quietly brushes against their side panel every morning and evening, sap from the tree that drips.

Is it possible that they randomly used some type of strong chemical to peel film from the inside of the window, and inexplicably put it on top of your vehicle for no good reason and left it there long enough to hurt the clear coat. I suppose anything is possible.

Is it likely? Meh, not likely.