First off, you can't waive negligence to whomever said that.
Of course you can. Are you saying that waivers / limitations of liability for negligence are per se unenforceable? That is just a misstatement of the law. There are probably tens of thousands of citations to this proposition, but we'll go with this cite from the Volokh Conspiracy:
The California Supreme Court issued an interesting decision this week on the enforceability of liability waivers in standard form contracts. At issue in City of Santa Barbara v. Superior Court, -- Cal.Rptr.3d -- (2007 WL 2027806), was a release from liability for "any negligent act" signed by a parent as part of an enrollment contract that allowed her daughter to participate in a camp for disabled children run by the city of Santa Barbara. The court ruled, 6-1, that the contract was enforceable as to allegations of ordinary negligence, but not gross negligence. This wasn't surprising; it is standard hornbook law that such waivers in the context of recreational activities are enforceable as to ordinary negligence but not as to gross negligence, although a few jurisdictions won't even enforce waivers for ordinary negligence. But it is interesting that, according to the court, it had never actually addressed this issue (although for decades Witkin on California Law has claimed that the majority rule applies in the Golden State).
Some States may have refined the definition of negligence to different versions and are calling the old negligence gross negligence but that is first year law school. It is the nature of negligence.
I was fairly attentive in law school, and overall I enjoyed the experience, but I never was taught this concept. I would like to think that that's because it's not true.
Oftentimes (but not in every jurisdiction) you can't waive gross negligence. You can't waive legal malpractice or medical malpractice. However, general, ordinary negligence? That's waiveable in a contract, so long as the waiver is clear, knowing, and voluntary.
You need evidence to contradict direct testimony that outweighs it. To say three people are lying without actual proof is pathetic work by Wells
There is a lot of nuance here. You're not arguing that a finder of fact has to accept all testimony as true unless it's rebutted, are you? Because that's obviously not the case.
Theoretically, there needs to be some evidence other than the fact that you know a suspect is lying based upon your assessment of his credibility. However, that evidence of guilt doesn't have to directly contradict the testimony you have rejected as non-credible. For instance, in the presence instance, Wells can find guilt is more likely than not based simply on his assessment of credibility and the fact that several footballs didn't conform to the ideal gas law, even if it is assumed that the gauge most favorable to the Patriots was used.
If there's a minimal level of evidence showing deflation of the balls, and then the finder of fact assesses the key witnesses to be non-credible, that's enough to sustain a civil level of proof. Piggy-backing on that with contradictory / non-credible testimony, lack of cooperation, etc. is probably enough for a finder of fact to reasonably find guilt linking Brady.
A lot is made about this being an arbitration award, but in terms of the evidence, I can't imagine any appellate court in the country would reverse the verdict for sufficiency of evidence if a judge / jury found the Patriots civilly guilty.
To me, the real issues are relate to procedure and punishment. I think it's crystal clear that a reasonable fact-finder could have found guilt here.