I Am Legend - movie betting

[Cry Me A River]

Historically, how many movies have opened for $50M+ in December? Or even close (including inflation adjustments)?

LOTR did $66M in 2001
Two Towers did $62M in 2002
Return of the King did $72M in 2003

So it's def possible, but, the bet is essentially that I Am Legend is the new LOTR? There's basically nothing opening against it, but still, unless Matchbook has some inside info (focus groups?) this seems like a sucker's bet. Does look very suspicious - Almost a bar stool pundit type bet (everybody agrees the line is ridic and the under is a lock... and everybody gets screwed).