Yes but they need a warrant to open any package from FedEx. New law, just read about it a few days ago. Not sure if it applies to UPS, it said FedEx specifically.
I think you may have misunderstood what just happened. Last week, the CA State Supreme Court ruled that a warrant is necessary for police to open a FedEx package:
http://www.latimes.com/local/lanow/la-me-ln-pot-warrant-20130627,0,315072.story
Note that this applies to DOMESTIC mail.
Also note that in this particular case, the police probably could have obtained a warrant fairly easily had they bothered to try. All they'd really have had to do was go to a judge and say "FedEx alerted us to a package that reeks of weed, we'd like a warrant to search it". I think most judges would have no problem issuing a warrant to open and search a specific package under those circumstances. The real issue here was that the cops didn't bother.
With a couple of very specific exceptions (eg packages sent to diplomats at foreign embassies) Customs most definitely DOES NOT need any warrant to open ANY package crossing from outside the country into the USA (FedEx or not).
Not only that, but FedEX itself reserves the right to open any of its packages for any reason it deems fit, and they don't need a warrant to do so. . .its in the contract you sign when you ship a package by FedEX.
So no, FedExing something won't help you here.