Not any USMC aviation mechanic school I ever attended.

The visual examination you describe ain't gonna tell you a thing about continued airworthiness UNLESS it reveals an ACTUAL non-airworthy item, which flaking paint isn't.
It might be an indicator of some underlying corrosion- more likely shitty prep work prior to paint- but it doesn't guarantee non-airworthiness, nor does an oil leak in a radial engine or exhaust soot stains.

It might make you uncomfortable because it ain't pristine and if that's enough to keep you out of it, fine, but saying the things you've said here is completely asinine.

I was there for the crash.  Hard start on number 4. Didn't see anything out of the ordinary as far maintenance issues (im a aircraft mechanic).

I asked how they could afford to properly maintain and fuel a B17 only getting 450 per head for 30 min flight? Asked about cost per hour and was told they didn't know.

I guess now we know.