The idea is that teams should select their teams from within the Top 25, unless prevented by injuries.
A player from the second tier cap like Moylan, who gets match payments for playing first grade - can get an exemption from the salary cap auditor to play, even though it will result in the club exceeding the cap. He was not given an exemption last week because Naiqama was available, and in the auditor's opinion there was not a justifiable reason for the Panthers to exceed the second tier cap.
The clubs, Phil Gould in particular - are opposed to this because they don't think the auditor should be able to dictate team selections, and also that the second tier cap has not kept pace with increases to the top tier cap. They also say it's too hard to predict how players will develop - in the Moylan case, at the start of the year he would not have been selected but for injuries, but now he deserves a place and it's unfair to exclude him.
I reckon it's fair enough for Moylan to play no matter what, but the cap needs to be structured so that teams can't stockpile an excess of first grade standard players.