門口喊的那句話
這就是核心畫面本身：三個字，一個二選一。
interjection · B1
The words children call out at the door on Halloween night. They mean: give us a treat, or we will play a trick on you.
「不給糖就搗蛋！」
核心畫面
Picture a child standing at a lit doorway on Halloween night, holding out a bag and offering the grown-up two choices in three words: a sweet, or a joke played on you. Everything else grows out of that doorway. The three words are the call itself. Walking from door to door all evening, saying it again and again, is the whole activity that takes its name from the call.
可以想成萬聖節晚上，一個小孩站在亮著燈的門口，袋子伸出去，用三個字給大人兩個選擇：一顆糖，或者被捉弄一下。其他的東西…更多收起
可以想成萬聖節晚上，一個小孩站在亮著燈的門口，袋子伸出去，用三個字給大人兩個選擇：一顆糖，或者被捉弄一下。其他的東西都從這個門口長出來。那三個字，就是喊出來的那句話。一整晚沿街一家一家走、把它喊一遍又一遍，就是這個以那句話命名的活動。From the word’s history
The name of the activity is simply the words the children say: a trick played on you, or a treat given to them.
活動的名字就是小孩喊的那句話：trick 是惡作劇，treat 是給的糖。來源直接寫明，這句話的意思是「不給糖就捉弄你」，活動便沿用了這句話當名字。
LDOCE sense 2 definition as supplied in the evidence packet ('they will play a trick on someone if they are not given a treat')
Two branches
那一整晚的活動
把門口那一幕重複一整條街，活動就直接借那句話當名字。
verb · B1
If children go trick or treating, they dress up in costumes on Halloween night and walk from house to house, saying 'trick or treat' at each door so that people will give them sweets.
去玩「不給糖就搗蛋」