The fines for unlicensed streetside selling are low, and the vendors have trucks they can move to another market as needed, so it isn't easy to catch them, yet the vendors can attract a crowd of customers wherever they go. Thus street merchants are called "urban cancers," from their ineradicability and mobility.
這樣的熱鬧氣氛是國人所愛的，而且攤販不必納稅，東西便宜，很容易聚集興起，但常會製造噪音髒亂、阻礙交通秩序，而被稱為「都市之瘤」。徹底取締攤販並不容易，因為罰款不多難收嚇阻之效，而且這裡抓得緊，他們就移到另一處。