And then it’s my job to look up the contract and find the specific portion you’re referring to? That’s not how this works.
With that said, yesterday I looked up one contract of carriage (it happened to be Delta’s, not United’s) and I searched for several relevant keywords that might be connected to this type of issue. I found nothing that supported your view. That doesn’t mean it isn’t there, but the onus is clearly on your side to produce the evidence that you believe supports your position.