A lock in some areas is an invitation for someone to stick something in it. Roadsters don't seem to have this problem as they have a cover over the lock face.
A wiring grommet covers the rear lock up nicely, by trimming the back off the grommet so it sits flush on the lock face. Just a tiny amount of glue will hold it tightly to the lock.
*** Be very careful not to get any glue in the lock itself ***
If you ever need to use the lock just peel it off.
It also gives a nice finish to the rear of the car; you have a choice of two different sizes depending on the look you want.
24mm grommet: Picture 1
30mm grommet: Picture 2