Spreading different cultures is always a good thing to do, in my opinion, but all depends on how it's done. In general, in my country at least, I see that people absorb only the most superfluous part of any given foreign tradition, making it a mere excuse to get drunk and/or compulsively buy stuff. To me, that's far from cultural or enriching.
I understand that a whole tradition that has been passing on from generation to generation for maybe centuries in a certain country is just not going to root in another one for the sake of it, but holding some cultural events related to all that legacy would be a very good thing to do, and would make people actually understand what they are celebrating and why. For instance, what the OP said of introducing students to foreign customs. I think that's pretty nice. And that's what I think it should be done: exposing people to the cultural aspects of foreign traditions and actually embracing all those different cultures, instead of turning them into reasons to drink or spend money.
Of course, I know that would take some more economical investment for governments, so it would probably not be worth it, specially because people can just search for information on the internet if they are interested. But, yeah, I think that would be a much better way to manage this kind of festivities.
Also, as TomaTito said, here in Spain we have the All Saints' Day on the 1st of November, even though it's not a tradition that I particularly like. If I want to honour my dead, I'd rather do it when I can be almost alone in an almost quiet place, and not in the middle of a crowd coming and going. I think that's kind of cold, too impersonal.
Anyway, happy Halloween to everyone!
I'm mostly a lurker now.
