I tested out the distance with a rangefinder. I had to run 300 m away to escape the effects. The inventory lag returned at full strength when I got back to 220 m.
I then tried to empty all the containers in my tents; removing mags and attachments, emptying vests, and dumping a couple of backpacks on the ground. The lag went away.
Next I tried putting some of the items back. I waited for 5 minutes, but the lag didn't return. I then ran 300 m away again, checking for lag all the way. When I approached again, the lag once again started when I was 220 m from the camp. This time it had reset, starting at 1 - 2 seconds and then slowly building up.
Tomorrow I'll be testing this out with a truck. A mobile desync generator could be... useful. Muhahahaha!!!