What is abusive ?

[Torin]

ganging up against the weaker instead of the stronger?
(perfectly legal but lame)

[Twan]

I think there is a little difference between sending diseased to the frontline (and one normal sized front squad) and using optimized archers decoys (1 or 2 units per decoy squad, many decoy squads in a checkers disposition, one empty space between them, two between them and the first big squads etc...).

Anyway, it's not really an exploit, just an annoyance forcing other players to use as much microgestion to counter it.