"That's probably the only time I've ever seen it called," Cassidy, now one of Claude Julien's assistants in Boston, recalled Thursday following a training camp session at Warrior Ice Arena.
That was until Thursday night.
At 17:06 of the first period, Bruins center Ryan Spooner was called for a delay of game face-off violation, after twice being kicked out of the circle.
For the 24-year-old Black & Gold pivot, it was another learning experience as he tries to solidify his face-off abilities.
"[Wednesday] night [was] not too good," said Spooner, who won four of his 16 face-offs, on a night when the Bruins struggled as a team on the draw, winning just 41 percent in a 5-1 preseason loss to Detroit.
Spooner captured 42.8 percent of his face-offs last season, his first full NHL campaign, and felt he was making significant progress as the year went on. Now, just a week into training camp, the Ottawa native is trying to regain his timing in the circle.
"If you would have asked me that question at the end of last year, I would have said I was getting a lot better," Spooner said of his development at the dot. "It's just going to be getting into the timing of things and competing a little harder on the draws. Again, I'm not going to be 60 percent all the time.
"There are going to be games that I struggle and it's those games where maybe I just need to go for a tie, instead of trying to win it clean. There's going to be games where the puck's going my way.
"Maybe not try to overthink and just go out there and play."
Spooner has been taking extra reps towards the end of each training camp session to get as much practice in as possible. At the same time, he has also been trying to pick up advantages in other places.
That's where the word "cheating" comes in. It may sound odd, but when it comes to hockey face-offs, taking liberties at the dot is often how many of the league's top centers gain an extra edge.
"[Wednesday] night, I got a penalty for trying to cheat," said Spooner. "It's basically just trying to get your body in there, trying to cheat on your forehand, turning your skates so that they're at a 45-degree angle.
"A lot of the time you can get kicked out; it depends on the ref. If the ref's strict, it's kind of hard trying to tie up his stick before the puck drops, little things like that that help out.
"But at the end of the day, it's just about being smart and knowing who you're going up against."
New Bruins forward Dominic Moore, who last season with the Rangers won 55.3 percent of his face-offs - one of the best marks in the league - emphasized that "cheating" is just a small fraction of the process.