Minuteman, glad to find you here.
I don't know about NCAA rules on the matter. However, I do know that the BE does not require member schools to play each other in non-revenue individual, sports during the regular season. If the BE sponsors the sport, member schools are only required to play in the conf tourny. I think BE schools playing Lax were allowed to opt out, because their programs were established prior tot the BE sponsoring Lax. If I remember it correctly, the BE voted to sponsor Lax only if it could get enough members to play under the BE banner. Also I remember that daU was not forced to join the BE in all sports, when it came it. It kept its baseball program as an independent.