Originally Posted by SDF_Traveler
(2) This one makes even sicker - Two weeks ago I sent some documents from Louisville, KY, US, to Melbourne, Australia, by UPS Express. The package
was supposed to take 53 hours (or shorter) for delivery (
many people pay a premium for this) - this is from the time I dropped it off to the time it was guaranteed for physical delivery. At ONT, US Customs "Export" Control took possession of the Express Shipment for an "Export Security Check" -
US Customs held this Express shipment of documents from being exported for THREE DAYS 
...? Why is US Customs interested in an ENVELOPE of documents from being EXPORTED?
I could understand if Australian Customs waned to hold/examine it, but US Customs? Thanks to US Customs, it was not only held for a period longer than it would take for delivery from SDF-MEL, but it took 152 hours door to door for delivery - four days late. The US Govt doing what it does best
/rant off
I realize this is off-topic but how sure are you that it was US Customs and not UPS that held the shipment? I've shipped with FedEx for years and while I've had shipments delayed at the destination end, I've never had anything at the USA end delayed on the outbound leg. AFAIK, US Customs isn't even alerted to what is leaving the US. The manifests are normally transmitted electronically to the destination country to prealert customs to what is coming and they can decide what they want to inspect.
In fact, the more I think about it, the more it seems it would be UPS not customs. When you shipped your documents, they are loaded with the other documents, most likely taken to the hub there in SDF, and I assume flown from there with a stop in ONT. At ONT, they aren't likely to be resorted as they are containerized. I don't think there is even enough time for US customs to look at a manifest for a loaded wide-body and decide what they want to hold and what they don't.
I think you're getting excuses from UPS. Give FedEx a try next time and see if they can do any better.