Hi Pfitzy, not sure what your getting at here? How could it advantage a club to run the same players for two games in a row?
Qualification.
When it gets towards finals times, lower division clubs will happily throw their top grade(s) in order to get their lower side(s) a trophy.
e.g. in Fifth Division, several clubs I played against had dropoff in numbers and so their Seconds would go out hard, then line up again and get belted in Firsts but try to avoid injuries.
The obvious complication here comes under the Qualification Rules in the Subbies manual, where you must have played the majority of your games for the Grade you plan to play with in finals. Issue is you played both, and only the higher one counts UNLESS you came off the bench.
So the requisite dodgy team sheet is submitted, and the names who played both grades are conspicuously absent from First Grade. Subbies check their records, and hey presto! Suddenly all these guys who were half-decent First Grade are awesome Second Grade players!