I remember a Law & Order episode in which a brain damaged boy was unable to speak, but was able to type words on a computer with the assistance of his caregiver.
After questioning the boy in court, the prosecutors realized what was happening. They then asked that the caregiver be placed where she could not see the cards the prosecutor was holding up, but where the boy could. When the caregiver was able to see the cards, the answers were 100% accurate. But, when the caregiver didn't have the ability to see the cards, the boy's answers were 100% wrong.
I can imaging how easy it would be for someone in charge of hypothetical Senator Fedderman's texting and closed captioning to get him to do or say anything they wanted.
Just saying, when you're dependent on others to do your job, who's really doing the job?