It is against the company policy to sell items inside the business center, especially during work hours. The employee must observe proper etiquette or else she will be charged with insubordination by the management and she might be asked to choose to work or resign and continue selling her stuff outside. It is better for her to ask the Human Resource office if it is allowed to sell items inside the business center and not to play dumb. She could write the management to allow her to sell items after work hours outside the business center and not to sell without the permission of the authority.