The US legal system is setup that if a company admits fault in something like this, it makes defending yourself much more difficult. Meaning if a lawsuit is brought about, it's not about proving innocence anymore, it's about mitigating the damages you will have to pay. Your lawyer is going to want to have as many options available to him/her to deal with your case during it's lifespan, and admitting fault before the lawsuit even begins will limit the lawyers options when it comes to negotiations and what tactics they can use in the courtroom.