I didn't read the site as saying that celebrating Halloween was an alien tradition over here - just the "trick & treat" thing. And I concur with that. Fifty-sixty years ago, when I woz a nipper, we certainly didn't do such things as knocking on doors demanding gifts. We went out to parties - often wearing fancy-dress of some appropriate kind - and played games, including really traditional halloween games such as "bobbing for apples" and peeling and apple so that the peel is removed in one strip, throwing it over your left shoulder, and seeing what initial it forms. The initial will be that of your loved-one-to be.