Is there any legal reason American Idol couldn't fix the results?

Sure it would be a huge scandal and would be sure to be the end of the shows exsistance but is there any legal reason AI can’t take all the voters results and then just decide for themselves who they’re going to kick off that week?
Could they be sued by anyone?
Don’t the contestants sign massive agreements that basically say the producers can kick them off the show at anytime for any reason they want to?

Wouldn’t that be legally-actionable fraud, as in the cases of the rigged quiz shows of the late '50s?