The simplest way to stop a cheater is for YOU to keep the score card. Grab the card at the beginning of the round and after each hole write down everyone's score! It's not like you're solving differential equations!
Fred, nice par!
Bert, three Jack for a bogey
Elmer, three on and two putts - bogey
Dad, topped drive, two in the bunker, left it in the bunker, four on and three putts - triple! Damn Pops! You made a mess of that hole!
How hard was that?
Don't try and pull...