Gas flapper

I just bought my 2000 Jetta after having much fun with my wife's 98 Wolfsburg. The flapper in the gas filler neck has broken off and is blocking the filler neck. I can put gas in, but it takes some skill and time. I'm taking it in to have it fixed (hopefully warranty, not sure yet), but I was just curious if this is a common thing or if maybe it appears someone tried to siphone from me. No marks from forcing the door open.

Thoughts anyone?

Thanks,
Matt

This is not a common problem with Jetta's. I have never seen this problem with any of the Volkswagens.