Just still be cautious and carry some insurance on your stuff. My brother broke up with his girlfriend, she moved back east. She packed all her stuff up in a PODS and shipped it home, and the pod dissappeared. PODS completely lost it.
However it's quite possible that something else happened to it that they don't want to admit. Like maybe their driver was DUI and crashed it.
I didn't test airtags at all but they definitely stack them pretty high up in a warehouse so idk if an iPhone is always going to walk by yours.
It also came in really handy when the driver claimed his truck broke down and he wouldn't be able to drop it off on schedule. I told them I could physically see the container in the storage yard and would like it delivered on the agreed upon date. They dropped it off 20 minutes later.