By Sam Laskaris Writer The British Columbia-based Ladner Pioneers won their third consecutive national Senior B men’s lacrosse championship this past Saturday. But members of the Six Nations Rivermen, who competed in the Presidents Cup tournament, believe the Pioneers did not play by the rules and should have been disqualified from the Canadian championships. Jeff Powless, a former general manager of the Rivermen who served as a team advisor this season, said the Rivermen did not follow a new rule that stated Senior B clubs could only have a maximum of five players on their roster that had played professionally in the National Lacrosse League this past season. The Ladner roster had five players who were NLL regulars in their lineup at the Presidents Cup tournament. They were Ryan Benesch,…