Each stone has a sensor on it to ensure players release their grip on the handle before the thick green line that runs across the ice, known as the hog line.
If they do, the sensor flashes green. If not, a red light shows.
In both matches Kennedy's stone showed green, but his opponents thought they saw the Canadian give his throw an extra push with his finger on the stone after letting the handle go - and the video evidence seems to back that up from the Sweden game.
But, as BBC Sport curling commentator Steve Cram asked former world champion Jackie Lockhart, is it actually cheating and does it make a difference?
"You should not be touching the stone after you've released it," Lockhart said. "If you touch it with a broom, it's burned and removed.
"He's released that stone, then poked it with his finger - I'm not sure why. Is it to push it a little bit harder because he felt he didn't give it enough?"
Fellow pundit Logan Gray suggested it was perhaps "muscle memory rather than active cheating", and after their win over the Czech Republic on Saturday, Team GB's Grant Hardie said that to call it cheating "would be a stretch".
Skip Bruce Mouat added: "I'm sure Marc didn't mean anything by it, it is just that he was caught doing it on TV. Now it's out there, it should be regulated pretty well, and hopefully by the athletes."