Being in your sixties doesn't mean you can't fight though, we had a guy who was 60 on one of our shows, Skip Hall, very fit ( in all meanings of that word!) very experienced and a good fighter. He's only just retired from fighting.
How big a problem is it though? Is it worth looking at systems to stop cheating? It's always going to cost someone something so who would pay for Id cards or similiar? An interesting problem.