It’s ludicrous to consider fuel to be contaminated once a sample has been drained in a clean container that is specifically designed for the purpose.
Its been in there literally seconds before you pour it back in after inspection.
What in Gods green earth could happen to a fuel sample to now make it dangerous to life and limb?!
Jetfuel is a different story as it deals with a entirely different universe of regulations and quantity.
Plane I fly we regularly land with 15-30 TONNES of fuel.
This fuel was pumped onboard in a country half a world away by provider which is not certified to do so at the destination, quality checked by a foreign company whose certification is not recognized ( pilot licenses/certificates anyone?) by the destination and therefor an “unknown” and hence the prohibition against draining/mixing/resale.
You can wear a Airline Capt Uniform while flying a GA SEP but that doesn’t make you so.
You can try and apply big plane regulations or procedures to little planes....doesn’t make it so.