Locked my only key in the trunk. Stupid, and the one time I broke my "don't set keys down in the trunk" rule.
Haven't had the cash to buy another key from the dealer, so spent the past few hours trying to come up with a solution. Caveat: the following will only work if you can see the key(s).
I finally realized that you can carefully lift the edge of the shelf behind the seat headrests a bit and see into the trunk.
So, carefully lifting the edge of that shelf without damaging it, just enough to see the key(s) using a small flashlight. Reach into the trunk with a straightened wire coat hanger, using the bent hook that allows the hanger to hang on the clothes bar in a closet to hook the key(s) and gently draw them up to and through the edge that you lifted up.
Obviously, this won't work if you cannot see the key(s) or get the hook into them somehow.
I hope that this helps someone else dealing with this issue.
