I'm sure I can find lots of people willing to sign such a document. Particularly if I pay them to.
My estimate is zero. Which makes your comment irrelevant to this discussion.
If you haven't met any that's ok
The person signing the legal documents is the engineer himself, not some "vagabond" retained by a lawyer. Evidently you are not familiar with how signoffs by engineers of record for things like bridges are actually done.
During the housing bubble, they'd just hire temps to sign things: https://www.reuters.com/article/robosigning-plea-idUSL1E8ML0...
We're not talking about a random person walking into a local bank and asking for a loan. We're talking about someone signing off as engineer of record for a project. The two cases are not at all comparable.
This reasoning is incredibly incredibly dangerous and there are countless very contemporary examples of it leading to a) exploitation and b) those well-to-do being let off the hook.
I challenge you to give one. You evidently are not familiar with how signoffs by engineers of record are made for structures like bridges.
Threat of having your life and career absolutely ruined pretty much does, yes. The key is that the threat has to be believed. For things like signing off as an engineer of record on a project, yes, the threat is believable. For being an investment banker who cooks the books, the threat of being punished might not be so believable, no, particularly if the bank can be portrayed as "too big to fail". But that's not the kind of project we're talking about here.
You evidently are not familiar with how things like bridges get built and how signoffs by engineers of record are made. Yes, you'll get caught, and yes, you'll receive the harshest punishment.