WR
As I wrote, I don't concern myself with how someone else navigates, and I am pretty sure there is not one other pilot in the UK who actually cares how somebody else navigates.
(If I was a passenger in a some spamcan and the PIC was dead reckoning, I would carry a GPS and quietly watch it).
The thing which I genuinely think is worth questioning is why this subject results in such long debates.
The GPS thing itself is irrelevant - until one gets onto CAS busts and measures which are being introduced probably largely to counter those.