In some jurisdictions they can charge you with "disorderly conduct" [1]. It can be argued that 3k+ people playing a game of hide-and-seek in a public store like Ikea does meet the following criteria:
- Makes noise that is unreasonable, considering the nature and purpose of the actor's conduct, location, time of day or night, and other factors that would govern the conduct of a reasonably prudent person under the circumstances.
- Creates or maintains a hazardous or physically offensive condition.