I just received my case A this morning. Thanks to the ebay asshat I bought it from who labelled it "weight gain"? WTF?. Customs decided to take a peek in my package. here's a picture, of course at this point I had already started opening it.

Love that yellow customs tape
Just opening the case wasn't enough the greedy bastards knew they were into something good, MRE's . Now they wanted to try out my Beef patty pouch

they made the cut right under the "US government property Commercial resale unlawful"
Of course I made sure some hungry customs agent didn't make off with some of my snacks. From this I can conclude that our customs doesn't seem to care about the small scale importation of MRE's. Of course this is just my experience so things may happen differently for others