There have been a limited number of cases of cheating in the Winter Olympics (far fewer than in the Summer Olympics), but that doesn't mean it's totally eradicated. Just ask Ortun Enderlein.
Enderlein, the defending luge champion, and her two East German teammates aroused suspicion by showing up just before their runs and leaving the scene hastily after. Enderlein won gold and her teammates placed 3rd and 4th, but upon closer inspection, it was discovered that their sleds had been heated immediately before the races, which reduced friction with the ice and resulted in faster times. The three were disqualified and the East German Olympic Committee blamed the affair on a "capitalist revanchist plot.