I put a thin (1/8in) bungee on anything attached via locline. I have a loop tied in the other end and this attaches to something on the camera system that isn't likely to go anywhere.
In good cases, such as my sola 1200, there's a solid ring to tie the bungee to. The other end gets looped into the main bungee that is clipped to my harness (so I don't lose the whole thing).
In other cases, you get creative finding something to attach. I've used cave line to attach a go-pro housing to my scooter handle. I've also used cave line to attach a flash diffuser to the flash or other solid bit. In the early days I lost a few diffusers during boat dives.
I also almost lost the sola on an early dive when boarding. Waves smacked me into the ladder and bent, then popped the loc-line. Fortunately we did a second dive on the same wreck and found the light very near the upline. It was then I added the thin bungee. So far I've not lost anything else.
I can take a photo if you want.