Yes sometimes that is a factor that servers struggle with, but sometimes you have to take the initiative and bet on them, even if you know they will lose. (Unless its something like a decap or dm, then its okay not to bet on them and just cancel the bets.)

A lot of the times, if you dont think anyone will bet on them, and someone bets big on the other player, its best to bet on the player you think will lose on the first couple of frames, because then people will see that you have faith in that player and you think they will win, so then they will bet on that player too. This will help even out the bets.