Bookworm, I wrote:
by your logic, it would be legal to descend from safety altitude on some half baked procedure, then pick up a published approach
You wrote:
So far so good -- that's not significantly different from vectoring.
But it is. The minimum vectoring altitude is not below safety altitude. The only time you would be vectored below the 1000' obstacle clearance is when on final of a radar approach (but even then you will still be getting the required obstacle clearance).