Just got of the phone with Apple (25 minute wait) and here is what Brandon of Apple's customer service has to say: Apple has a policy that says it won't start a trace until three days after the scheduled delivery date. Why? Because the computer might just turn up. Yes, "it might just turn up."
This apparently happens with more frequency than we care to think. In Brandon's case, he said his most recent call with a similar lost package complaint was only four days ago, and he is one of 200 Apple customer service people.
I pointed out to Brandon ("We're all trying to do our best.") this means me calling Apple again to start a process that should be started when UPS tells me it can't find the MacBook and I pass that on to Apple.
But no . . . now I have to wait three days to start a trace process that only Apple can do.
By the way, Kim from UPS hasn't returned my call.