I did a similar thing. We had two identical pairs of AirPods. One pair had a bad battery on the right earbud.

I thought those were mine, which had a specific extra warranty purchased from the store (Not Apple's own). Returned those to the store to get it fixed. Turns out they store and check the Device ID and I found out we've switched pods with my SO at some point.

They wanted a "spurious return fee" that was more than the value of the AirPods. I just didn't pay it and they destroyed them.