Goals are reviewed by a group in Toronto and final determinations are phoned to the refs in each arena. the goal line camera is pretty good and they can usually get a good shot of goalie interference, puck crossing goal line, etc. They also have a camera set up on the blue line to see if players are offside before a goal is scored.
Agree that there are small, inexpensive hi def camera options that could give more conclusive evidence on sidelines, backline and goal lines.
Heck you could have small, quiet camera drones hovering over the end zone for an entire game. Also could put a chip in each end of the ball that would know the absolute position to the foot - of where the ball ends up after each play - for touchdowns, first down spots, etc.
This is all readily available technology but probably scares all the old guard owners who probably can't work a touch tone phone at this point.
