This is sounding a lot like a profession making it illegal for others to do anything that could decrease their own income.
It's not clear to me what calculus should be used to decide "the public interest" much less what calculus should be used to threaten otherwise peaceful adults on its behalf.
Further, while it is good for engineers to have a sound understanding of what they're doing, the issue at hand is whether or not one has the permission of some state bureaucracy. While the latter may intend to yield the former, one should take care not to unnecessarily conflate them.
Someone presenting an argument to whomever (the public, the city, etc.) has every right to make their case to the full extent possible (implied: honestly, without representing themselves falsely). No one has represented themselves as an engineer falsely so... Uhh, this sounds like a big load of crap, both specifically and generally.
I'm arguing that the implicit argument that state engineering boards exist and act [primarily] to protect the jobs of engineers overlooks the benefits of ensuring that people actually representing themselves as engineers are suitably qualified and competent. I also seriously doubt it's in the financial interests of engineers to reduce the amount of paid work they need to do to to alleviate public concerns over their plans.
Just stick to friends and/or people who won't sue you.
If you can get a hold of a medical stapler they're even easier.
In other words, utter fucking bullshit.
That said, it's definitely not a bad idea to keep your CPR training up to date. Mine was renewed last December.