Impressive,
I believe, rather than being rostered into discretion, it is moreso instances of untrained Operations staff, on or near to the day, re-rostering the pilot without understanding the regulations.
A simple explanation of 'excuse me sunshine, is that not illegal?' to the Ops guy would be sufficient and which is understood to be happening but it's much more sensational to say 'rostered into discretion', a little bit like 'BA crash landing in Entebbe', attention seeking I guess.
Yes, Emerald does have it's problems but many of them are 'industry standard', much of the complaints seem to be guys in their first airline believing they are the only ones hard done by and once they move on from Emerald the streets will be paved with gold!