I'm quite certain that there are too many readers unable to detect the sarcasm, so to clarify:
The large overtime payment you deny the other guy when you work a G day for the tiny G day callout pay is the same large overtime payment the other guy will deny you on another day.
There is a reason the company calls guys on G days while others are already sitting reserve as per their roster....and it's not to because they want to give the G day worker his tiny little bonus.