If I had to bet, I'd put my money on the Ag Inspection people. They are
getting really tight on anyone shipping interstate who doesn't have all the
certs for pests. Even if you don't have the pests they confiscate the
plants and distort them. This wasn't too much of a problem until recently.
The laws were there but enforcement was hit or miss. This is another fallout
of the 9/11 paranoia. Everything is being inspected in detail. FedEx is
just as bad (if not worse) than the USPS.