How about this instead?...
"FBI researchers have successfully used the procedure on test computers, but a waiver that infected machine owners are asked to sign releases the feds from any legal liability should things go wrong."
"At no point do federal authorities have any control over infected computers or access to personal data residing on them, and owners who want to opt out of the disinfection routine may do so."
And if they refuse?
How about this: If they refuse to let the FBI clean their machine(s), then they will be given, let's say, 24 hours, and if their machine(s) are still infected, they will then be judged complicit in the damage that the malware does, and be taken to court and be subject to whatever sanctions the law allows.
Or this: make computer owners/users legally responsible for keeping their machines clean, and give ISP's the legal right to disconnect any zombified machines.