A) It doesn't as long as you buy seat covers that are airbag compatible. Different cars have different types of airbags, e.g., side-mounted ones or built-in seat airbags. These days, in-built side airbags are the most popular ones. When a crash happens, the impact airbags burst through the seat and inflate. If you have an incompatible seat cover, the airbag will deploy inside the cover, therefore not protecting you in the end.