Hi placo1,

I don't want to claim my syphoning method as particularly safe, but I have used clear plastic fuel lines to insert into the tank and with the other end close to the ground give it a good suck. The clear hose lets you see the gas.
If you have a lot of hose, sometimes it works to insert it into the tank, then close the outside end and pull the hose out quickly and under the level of the tank.

You need to have gas containers ready to put the hose into. A funnel also helps.

I have 3 of those emergency gas containers for the lawn mover etc. and while No 2 fills, I can empty No 1 into another car.

A hand-operated pump, of course, would be your first choice.

Good luck at the exhibition

Reinhard Kreutzer