No matter whether a team loses by its own goal or the goal scored by the opponents, a loss of the match on the team we bet, means the loss of money. I don't think that we need to blame that we lost the bet because someone from our team did an own goal. Of course, it is also co-incidence and no player does it deliberately.
Although there are not a lot of matches where the game is lost due to an own goal, but still the gambler should be ready for any outcome of the match in any way.
Own goal is a mistake that could come from the best defender. So, it'll be hard to assume which team would score an own goal. It all depends on the pressure of the game. There are times when the attack would be tough a player may be forced to make such mistake in his try to save a goal. Also, with the way it happens, viewers would think the player was careless. And blame him for their losses. Blame is something that will always happen, nobody easily blames himself. It's nothing to bother about if a player losses a game, through an own goal. The cause of the losses doesn't vital role in changing the result. The player just have to accept it, as mentioned above.