That might convince a judge, sure, although it's still possible to fake the evidence... but I would argue the vast majority of people who claim to have clean-room RE'd something absolutely did not go through anything close to this process.
I don't know anything about the majority of developers, and I think sweeping claims about any group require strong evidence, which seems lacking. But there are plenty of examples of companies that followed such a process, and succeeded in court: https://en.wikipedia.org/wiki/Clean-room_design#Examples
I think when someone fails to produce any evidence of a clean-room process being followed when they claim it's clean-room, is probably a good indicator. Yea you can call that "trust me bro" if you want, I won't be upset.
