Don't - arrange to meet somewhere halfway!!!
I sent a bass earlier in the year through Citylink. Had an on -line chat with one of their representatives over insurance costs to which I decided to go with them. The bass was packaged very well inside a hard case and then packed again into a guitar cardboard carton.
It arrived damaged. The end strap pin had pierced the case causing that to break and there was some form of fracture split to the lacquer on the guitar itself. I'm fully insured though right? NO!!!
When it came to making the claim, hidden in the small print was the clause that the maximum payout for damage in transit would be £100 irrespective as to how much insurance was taken out in the first place.
Was I misinformed? Yes. If I'd have known the above then I wouldn't have sent it...
Be warned and check the maximum amount you can claim for.