Many of the posts I have seen on FanNation and other sites (including game posts, comments, and blogs) suggest that there are conspiracies rampant in sports. In particular, league officials are supposed to have scheduled games to the advantage of one team or another. Game officials are to tilt their calls to help a preselected team win for some reason.
The reasons vary from simple (but unsupported) statements that <so-and-so referee> doesn't like <team name> or <the league> will favor <team name> because it is a big money market, and the like. The reasons are endless and quite unconvincing.
Leagues do strange things sometimes, and so do referees. Both are human. But aside from the case of Donaghy (NBA referee involved in betting on games he officiated), the presumption is that games are scheduled and called "cleanly."
I do feel that there tends to be a bias toward the home team, but I don't feel it is a strong one. The reason for this bias can be understood by anyone who has tried to umpire a Little League game with angry parents screaming. I am pleasantly surprised that the officiating isn't even more tilted toward the home team.
There have been games which have been badly mauled by the officials, of course. But I have not seen evidence that this was done intentionally by the officials any more than I have seen evidence that this was done intentionally by the players (the "Black Socks" excepted, of course).
Further, it stretches my imagination that an official should bias a judgement. This is not the image that most game officials have of themselves. Like a team that has just lost a close one; when they butcher a call, they pull themselves together and go on to the next one resolving to do better.
And I cannot image any official taking orders to tilt a game. Not only does this violate all the self-concept of arbitrators, but it would involve too many people to keep secret. And despite all the claims of conspiracy, there is no one in a knowledgable position blowing any whistles on these plots.
Conspiracy theorists will say that it is still possible that game tilting is occuring. Maybe so. But to convince me that it is likely, you will need evidence. And at this point I haven't seen any and doubt whether it is there.