L/O Completion

It largely depends on what the contract says.

When I turned in my fleece to owe, er, lease truck, after 9 weeks of going into deeper debt each week, I could've cared less what they did with it. I even returned it with empty fuel tanks (kind of stressful, but I timed it just right), just the way I got it. But, just to cover my trailer overhang, I took it in to a mechanic and paid for a full inspection, and took pictures of everything, especially improvements I made, and kept the receipts for all repairs I made during that 9 weeks (there were a lot).

The truck was "sold" for only $5,600 less than what I owed for not completing the lease, and I count my blessing on that one. Seems there was a surge of interest in trucks of that make and year with automatic transmissions, with that engine (for the life of me I'll never understand why). I expected they would have to auction the rig off after what I had been through with it, owing tens of thousands of dollars.

If you did what I did (photos, take to a mechanic), that should be sufficient to cover yourself legally should the carrier refuse to do an inspection with you present.