Match fixing happens everywhere but it is only easier to detect in the smaller leagues
Various sports are guilty of this as well. In my opinion, individual competitions
for instance horse racing and boxing are more vulnerable to such manipulation compared to team sports.
In the case of under table agreements the latter would demands silence and secrecy from every player involved into such corrupted matches. Regarding the smaller leagues, agreed, here this phenomena is much easier to detect compared to high leagues.
Match-fixing in team sports is often carried out by senior team members or coaches without the players' involvement. It can be more difficult to detect because players are less likely to notice such manipulations within their own team.