Good Business Sense:
Do you fly in Class G or is it always on airways high level in something heavy?
Class G or class A it makes no difference. You cannot descend below the altitude approved by the state, which is either your safety altitude or the aerodrome minima if landing.
You present information/regulation relating to "aerodromes" to make your case - there is a whole world out there that doesn't fly to/from departure, destination and alternate aerodromes - your take on the LAW is out.
"Aerodrome" is defined in the regs as
anywhere intended to be used for the arrival, departure or surface movement of aircraft.
ShyTorque:
There are obviously some here who still don't properly understand SERA 5015 (and its equivalent in the UK ANO in previous times). The "Safety Sense" leaflet, although giving advice, is not the legal definition. Check the wording of both.
I expect everyone understands 5015. What seems to be eluding you for some reason is that 5015 does not allow you ignore all the other regulations. SERA is not a complete stand-alone set of regulations, it is only a common core. If you go to the ANO and/or Part-NCO you find the other stuff a private pilot has to comply with.
The "Safety Sense" leaflet, although giving advice, is not the legal definition.
Let's call it what it is then. It is how the competent authority interprets their own legal definition
Here it is again:
"User-defined approaches can be dangerous and are not authorised."
And here are the current regs again:
ANO:For flights under Instrument Flight Rules, the pilot in command must select and use aerodrome operating minima for each departure, destination and destination alternate aerodrome which must not be lower than those notified, prescribed or otherwise designated by the relevant competent authority
Part-NCO:
For instrument flight rules (IFR) flights, the pilot-in-command shall select and use aerodrome operating minima for each departure, destination and alternate aerodrome. Such minima shall not be lower than those established by the State in which the aerodrome is located, except when specifically approved by that State
And here is the ICAO stuff it is based on:
ICAO Annex 6 2.2.2.2 Aerodrome operating minima:
The pilot-in-command shall not operate to or from an aerodrome using operating minima lower than those which may be established for that aerodrome by the State in which it is located, except with the specific approval of that State.
2.2.4.7.2 Aeroplanes operated in accordance with the instrument flight rules shall comply with the instrument approach procedures approved by the State in which the aerodrome is located.
Note that in no case is there a caveat that made-up minima can be substituted for approved minima even if you really really intend to land.