I am the commish of a H2H points league. During the off-season, I hammered out several gray areas in our league constitution to limit loopholes. The very first rule states that teams must have 1 player at every offensive position (3 for OF), 5 SP, 3 RP and 1 of any other pitcher. Thinking this was simply an informative gesture and not a rule that actually needed to be enforced, I didn't go into detail on punishment if this rule was to be broken. I did write that "invalid" rosters would score 0 points for that day, but the rule was more towards having a full 23 players on the roster and not harboring DL players).
When I reminded teams of this requirement, the two teams who were currently breaking the rule complained and made a big fuss about it. They demanded a vote (Any "major" league rule changes where there is a gray area require a vote). Not surprisingly, my stance won, a lot of teams felt the same way I did. The outspoken owner, who lost, thinks this should take effect next year and he should have freedom to make his roster as flexible as he pleases. My counter is that the roster requirements are in the rules. It has to stay. The debate would then be what the punishment should be.
My thinking is, because the roster requirements are in the constitution, a roster without a certain position is "invalid" and should suffer similar consequence.