Canada's Chelsea Carey remained undefeated with a 10-2 win over Erika Brown of the United States on Sunday night in Draw 5 of the women's curling world championship.

Both teams had heated exchange with officials in the fourth and fifth ends over a disputed hog-line violation by Canadian third Amy Nixon.

Nixon's sensored rock — which blinks red when its handle isn't released in time — indicated she had hogged her throw in both the fourth and fifth ends.

The Canadians claimed in both instances that the handle malfunctioned.

"It was not a pleasant feeling. It was a difficult situation," said a terse Nixon, who added with a laugh. "I'm still trying to get over it, actually."

Despite that controversy, Canada (3-0) was so dominant that the Americans (0-3) offered the handshake after six ends.

Carey and her teammates play Anna Sidorova of Russia (2-1) on Monday morning in Draw 6, then Margaretha Sigfridsson of Sweden in the evening draw.

Canada came out strong in the first end, with Carey making a difficult shot to take out the American's one rock with a deflection of one of her own stones for four points.

Brown just barely made a draw to earn a single in the second end, to cut into Canada's lead and make it 4-1.

Electronic rocks fan the flames

Canada lost its fifth stone in the third end over one of the disputed hog-line violation. Canada called a hog-line violation on itself after the rock's lights turned red following Nixon's throw. Her teammates burned the rock because of the red light, but Nixon argued that there was a handle malfunction, as her hand was well clear of the handle before the hog line.

Brown and her rink argued that as the Canadians had burned their own stone, it couldn't be re-thrown.

"I'm not one to go over, but since we don't have a jumbotron or a screen here it's very difficult to know," said Nixon, who had told officials during practice that her rock's lights had been malfunctioning. "The biggest thing about that is I just wish someone had been able to tell me on the replay if I was over or not because either you're over and you accept it or you're not and you start to ride the officials.

"To play in a world championship and be in that situation is, needless to say, not my favourite thing I've ever experienced."

Carey missed a take out on the next stone, sailing her throw through the house without touching anything.

Canada recovered, though. Carey threw a raised double takeout, adding to her 5-1 lead and bringing the largely Canadian fans to their feet at the Credit Union iPlex in Swift Current, Sask.

Debate flared up in the fourth end, as Nixon was called for the second hog-line violation. Instant replays show that she had released the handle before the line. Canada was allowed to re-throw, this time and red lights would be ignored for the rest of the game.

"Technology's great but, as far as I'm concerned, just give everybody handles without sensors in them and if you have a problem with the other team then call an official out or something," said Carey. "We play at all the other events, all the Grand Slams and everything, without sensored rocks.

"After experiencing that, that would be my preference because you generally don't have other teams doing that and it's just really unfortunate to get punished for something you don't deserve."

Brown drew for the single to make it 5-2.

Carey responded with a single in the fifth, then added another four in the sixth when Brown came up well short on a draw. The Americans immediately conceded after that.