We all would have had to demonstrate a precautionary landing for a restricted PPL or GFPT. Far better to find a good spot to put down and live to fly another day while you still have fuel than to push on.
Is your post a wind up?
Say you figure out you are 5 minutes short on your fixed reserve at your ultimate destination being an aerodrome with a 2km 30 metre wide asphalt runway with refuelling facilities, you are going to land in a farmers paddock 5 minutes short of your destination and potentially kill yourself running in to power lines or risk bursting into flames with all the useful fuel still in your aircraft when you hit unseen small obstacles when on the ground?
Suit yourself....