Sam Spade wrote:
When within 10 degrees of the published course.
There is no policy or rule to support that.

Yeah, the FAA is so incredibly disfunctional that it is literally
possible to have a 'properly' (meaning in accordance with TERPS)
designed approach flown 'correctly' (meaning to the level required to
pass the instrument rating ride as per the PTS) with functional
(meaning working well enough to pass the mandated operational checks)
equipment, and still slam yourself into something.

Check out the LVJ VOR-B.

Michael