Another option is you can have them delete the old key from the CAS memory. The metal key will still work in the key hole but they won't be able to start the car or unlock with the remote.
You can then also do the keyhole delete on the driver's door, but there will still be the trunk keyhole.
AW/Terra | ZSP | ZPP | ZCW | iDrive | CA
Mods: BC BR coilovers | Blacklines | M-tech rear | dual exhaust | M3 steering wheel | BMW SSK | ZHP shift knob | High-kick CF spoiler | NBT Retrofit
M3 front control arms | M3 rear guide rods | Manzo rear toe and camber links | Monroe rear shock mounts | Varrstoen ES1 19x9.5+20 Front, 19x11+25 rear