Blooper

In the frontal shot of the Claybourne's house while everyone is in bed, there are no tire tracks in the snow. But when Porter sneaks out of the house a while later, there are fresh tire tracks from his SUV already leading away from the house.

When the Claybournes arrive at the cabin in their Hummer, Mr. Clayboure gets out with his shotgun, walks toward the cabin and shoots the bear suit. When we cut to Mrs. Claybourne's reaction, the shotgun is leaning against the rear tire.

Eugenie tells Porter that her father won the gold medal in the biathlon at the 1952 Winter Olympics. There was no biathlon at the 1952 Games. The biathlon, developed from military patrol (a team event held in four prior Olympics), debuted as an individual event at the 1960 Games.

When Porter and Griffin are having lunch in the hotel the girl (who becomes Porter's first affair) is playing a double bass in the lobby. The soundtrack music, apart from being very obviously not synchronised with what she is playing, is a viola or possibly violin - definitely not a bass.