Going through the back seat not an option. MBZ puts the fuel tank their. I liked the credit card option untill I looked at another MBZ. The latch is inset into the trunk lip and so is the sliding bolt which is in fact, just to the left of the latch. The mating parts on the trunk lid are major fixed hunks of forged metal that engage the latch and sliding dead bolt when the trunk is slammed shut. No movable parts on the lid itself. Look at any MBZ trunk lock to see what I mean. "Engineered like no other car in the world" Boy ain't that the truth. Drilling sounds plausable but targeting the correct location is going to be tough. Giving some serious thought to giving the Dealership a wack at it. Last resort....