I feel their denial is totally plausible but they do have a history and a victim named Kelly Currin Davies stating otherwise...
From Swimming World:
USA Swimming spokesperson Karen Linhart released the following statement in response to the lawsuit:
USA Swimming is not a party to the lawsuit between Dia Rianda and Mark Schubert; however, because that suit makes various gratuitous accusations against USA Swimming, we will address the false premise underlying those accusations.
The resolution of the relationship between Mark Schubert and USA Swimming absolutely did not involve any cover-up of alleged sexual misconduct by Sean Hutchison or any other person. Rather, because of USA Swimming's commitment to safe sport, the agreement between USA Swimming and Mr. Schubert specifically required that if Schubert had, or in the future, received reliable information involving a sexual misconduct Code of Conduct violation by a coach or other member of USA Swimming, he would bring that information to USA Swimming in writing and would testify at a National Board of Review proceeding if requested to do so by USA Swimming.
Regarding Bill Jewell, USA Swimming cannot comment on ongoing investigations. However, as a matter of process, when USA Swimming initiates a coach investigation, it immediately notifies the employing club. As per the Amateur Sports Act, membership status cannot be affected without the opportunity for a hearing. Employment decisions during investigations are at the discretion of the employing club.
They are on the record now stating no cover-up was instigated with Mark Schubert despite what was written on Page 8 - lines 5-18 of the complaint - see link below:
Full Dia Rianda vs. Mark Schubert/GWSC Summons and Complaint: [Link]However the phrase they used was cover-up rather than confidential agreement. In the end it will come out once Mark Schubert and Dia Rianda are deposed. Then we will have a more clear idea as to whether "hush money" was paid or if it was simply a buy-out of his contract.
Kelly Currin Davies rebuttal response as quoted in the Washington Post:
“I have stated all along that numerous people in the swim world knew what Rick Curl did to me,” she said in a statement Tuesday issued through her attorney. “It was the worst kept secret. I read the lawsuit filed against Mark Schubert. I am angry in reading that USA Swimming failed terribly when they had an opportunity to act against Rick Curl when coach Schubert informed Chuck Wielgus on numerous occasions about Curl’s molestation of me.
“The fact that Chuck Wielgus and USA Swimming allegedly tried to cover up for Rick Curl by forcing Mark Schubert to accept hush money in return for signing a confidential agreement is outrageous. If USA Swimming has any integrity they would fire Wielgus and the rest of the staff that continues to protect sexual predators.”
One thing that bothered me was that either USA Swimming under-reported or the Washington Post under-reported stating that USA Swimming has caught 16-offenders in the last two years. It's not that low; isn't it more like 50 or 60? I suspect they are trying to make the problem seem smaller than it is.