One time I flew home from Rome, a long trip; before boarding the plane I bought a salami of some sort (long time ago now, but I remember that it was expensive for Ms. Thrifty Traveler) and when I arrived at customs in the US the guy zipped the meat product right away - which annoyed me a lot, though I didn't verbalize my feelings. Since then I've learned about many products one couldn't keep. I must have looked surprised, pissed off, and sad, in that order. The customs man wasn't mean though. I wished there was some warning at the Fiumicino Airport shop, but that's silly, it's a big airport and I presume countries have variable import rules.
..Nothing like the situation that happened for Olivier, which was completely ridiculous.
I suppose that now one can google what one can import through customs of whatever country.