Great secret hiding place for key

I should probably keep this to myself, lest it become not-so-secret, but I'd like to share with the PriusChat community.

I like to have a backup for getting into/driving my car in case I lose my key while I am out and about. I have the transponder key hidden inside the car in a Faraday pouch, so I just need to hide a mechanical key outside the car somewhere so that I can unlock the door.

I came up with the inside of the rear wiper. First, to get to that area, you have to know how to unlatch the wiper, so its pretty secure to start with. Second, its completely hidden.

Below is a photo. I've used two zip ties to secure the key (which actually fits almost perfectly into the nook) and then a used double-sided mount tape from 3M to secure a single-edged razor blade (to cut the zip tie).

I know that it would just be easier not to lose the key in the first place, but this puts my mind at ease that no matter where I am, I can always get into the car and drive.