The term "pack 'em in" typically refers to squeezing as many people as possible into a confined space, often in a crowded or cramped manner. An antonym for this phrase would be to "spread out" or "space out," suggesting a more comfortable and open arrangement. Other antonyms might include "break up," "scatter," or "disperse," which imply a movement away from a centralized group. Depending on the context, additional antonyms for "pack 'em in" might include "thoroughly organized," "selectively curated," or "luxuriously spaced," each invoking their own set of associations and implications. Ultimately, the choice of antonym depends on the specific situation and the desired outcome.