Here is a review left by a customer on a product. Would you say he was satisfied or dissatisfied?
Title: Not recommended by police officers
Review: We had our car seat checked at the local police station, and the safety officer recommended that we not use anything under our car seat. In case of an accident or a problem with the car seat, using any additional product (such as this mat or an attached fleece covering) may void the warranty of your car seat!
