The Hayden dismissal might be an example to use in this instance - say he'd been given not out. Firstly, where at 1st glance it looked like it may or may not have hit him in line, would the fielding team go for a referral anyway? I mean, it's not an obvious thing like say Ganguly's stumping in the 1st innings or say Symonds at the SCG. Then if it's referred, is the umpire's starting point that the decision stands unless an obvious error so even if they think it hit in line they say "it's borderline so not out", or do they say "No, looks good enough for me, he's out?"
They need to set these parameters (if they haven't already) so everyone knows how it works. Like in the NRL over here, we have the video ref, but everyone knows the video ref is not allowed to look at whether a pass has gone forward, because of camera angles, so the decision making is taken frm them to that extent. Do they have anything like that set up?
I think referrals are great, but the ground rules on things like this need to be sorted out IMO. Anyone know if they've been set out?