Perhaps coming clean would expose her to a Lance Armstrong type legal claim in the US. Lance was sponsored by the US post office, Lance lied about how he performed the sporting task he was sponsored to carry out and is currently being sued for it by a third party under federal whistleblower statutes that include a triple damages clause. Now Boeing is a private company but they do receive federal contracts and funds.
Perhaps she's been advised to keep quiet so as not to step into the sights of a opportunist ambulance chaser.