Fred,
I haven't fished a lot of bank matches, but can see your concerns with regards to how things should 'pan out' so to speak.
Hows this,
For example.... 8 pegs, and you caught on 5 of them, resulting in 15 fish, for a 2lb average, equals 30lb of fish..... However, this is the twist,

, if you blank on a peg, which would be 3 pegs in this example, you lose say, 1/2 lb or 1lb from you total bag weight, which the marshall/controller would mark on his own or anglers card: ie: Angler 12, 0 Fish. This would encourage anglers to get their heads down and winkle a fish out from each peg to at least compete for a place at the end of the match.
Just an idea....
Carl