Yes, referee's could still make errors, video technology isn't completely definitive, at the end of the day, it's still a human decision after reviewing whatever incident. Rugby League won't rule on forward passes because with all the angles on offer to the video referee, each shot can be deceptive and the decision can take much longer to rule upon. I'm sure there would be certain things the video refs in Football couldn't rule upon. The rules haven't been changed in Rugby League to pander to the video referee system and any video ref system in Football wouldn't have any rules changed.