He emphasised there was room for technology in the game but said too many incorrect decisions were being made on groundings.
"I think when we're looking at groundings it's got to be done in the motion, it can't be slowed down," Ennis said.
"I can understand if someone's foot has touched the sideline or if a ball has been placed on the line. In those sorts of things it's wonderful to use slow-mo. And with the technology why not.
"But in terms of placing the football, there's so many different ways that a football gets put on the ground. You've just got to look at it in real speed. That's the common sense behind it.
"You can't be slowing it down frame by frame because your natural reaction when you go to put a football down, you've got to open your hand to place the ball down."
Ennis said he appreciated human error was part of the game but it was hard to take when it almost cost the team, who are clinging to the edge of the top eight, an important win.
"It was a try every day of the week and it didn't surprise me yesterday that Tony (Archer) had to come out and say that," he said. "It's just fortunate for us, with how important that game was and how much we put into it, that (the win) didn't get taken off us."
-AAP