"The seat you have selected is designed for people under X lbs or with a waistline under Y inches. Exceeding these limits significantly may impact the comfort of adjacent passengers. In the event that other passengers are affected, you may be asked to move to a different seat without an adjacent passenger, to upgrade and move to a seat with higher weight/size limits (such as first class), or if no acceptable options are available, to exit and reschedule on a different flight."