Actually professional poker players recognize that west coast players are at a disadvantage when playing on the east coast, and they are at an advantage on the west coast, precisely because most poker is played in the late afternoon into the late evening.
I think the corollary isn't entirely the right comparison, I guess is what I'm saying... I think it's pretty clear that night games which kick off at 5 or so Pacific time should be the same everywhere -- as the kickoff time is at the same body clock time regardless of where the game is played. It makes sense given the physical nature of the games that west coast teams might have an advantage over east coast teams with the late starts. For the east coast teams, the game isn't ending until nearly midnight, when the body wants to be asleep.
Conversely, I think it's probably true that if you looked at 1:30 Pacific time starts, and compared games played at that time in the west vs. games played at that time in the east, you'd probably find that controlling for everything else, the outcome would be pretty similar between those. The east coast teams would be at body clock time 4:30 going through 8:00 or so which is fine.
Finally, I think 10 AM Pacific starts would clearly show a bias towards the east coast teams.
This is just MHO, but the critical point I'm trying to make is that prime time games start at the same body clock time regardless of where the game is actually played -- because the start time of the game is shifted locally to line up with 8:30 Eastern.
