I think they are doing challenges wrong. If a coach challenges a play, then every aspect of that play should be open for and subject to examination. Even when there were two, and possibly three available to each team. Specifically, two examples come to mind - the Saskatchewan game where Jones challenged the catch (replay showed clearly it wasn't) and won, the DD then challenged immediately the exact same play for PI (again replay showed that clearly it was) and won. The first challenge should have been enough for the ref's to make the call "the challenge is upheld, the pass was incomplete, upon further review a call of pass interference was found on the play by number so and so, yada yada yada". Then last night the PI call where Maas lost his mind at the end of the first half - as soon as that challenge was launched, the ref's should have the option of calling something else on the play - I think replay showed that offensive PI was actually a more likely call there than defensive PI, and if there was going to be a change in call, that would have been it.