Let's say the commissioner of a dynasty league discovered that someone tanked during a few games at the end of the season (Year 2 of the league) to get a better draft pick in this year's upcoming rookie draft. There aren't any explicit anti-tanking rules and the way the rookie draft order is calculated for the upcoming draft has been posted since the league started (i.e. it has been posted and disclosed to the owners for over two years). The owner that tanked had a screenshot of a text message where he and the commissioner discussed starting inactive (bye week, injured, suspended, free agent, retired) players. The tanking owner asked if it was something he could do, and the commissioner said that "if you don't have anybody else to start, then yes, but if you just don't want to, then I don't know." The tanking owner then pointed out that the site did not prevent someone from starting inactive players, to which the commish responded "Cool. Yeah." The tanking owner understood this as a grant of permission to start such inactive players, and a pro-tanking position in general. The commissioner claims that the owner never explicitly asked about tanking, and as it turns out, the commish is actually strongly against tanking (something that was not known until now).
The commissioner collected dues for the upcoming season (the season for which the rookie draft will take place), but he did not like the fact that somebody tanked. On the other hand, the tanking owner had a screenshot of conversation where the commissioner says that the order of the draft "must" be the way that it is currently posted in the league's bylaws. However, the commissioner still decided to change the draft order regardless, because he is really anti-tanking. He changed one of the tiebreakers from total points scored by starting lineups, to total points scored by each team's optimal lineups.
For what it is worth, the tanking owner has played in leagues where tanking has occurred, specifically, leagues where teams were allowed to bench their star players in order to lose a game (to get themselves a better matchup in the first round, a better draft pick, etc.), or to bench players in order to secure a win (prevent someone from scoring negative points). However, the commissioner has never seen this tactic in 10+ years of playing. The tanking owner also believes that tanking happens in real life, but the commissioner is of the firm opinion that it does not. On top of that, the tanking owner has hard evidence that tanking happened in Year 1 of the league, but the commissioner is unaware of this.
It is also worth noting that in the final game of the season, the commissioner did spot the tanking and after a brief exchange, the tanking owner agreed to set a new lineup because, although he thought it was fair game, he just didn't want to "start any drama" among the league members. During this exchange, the tanking owner showed the commissioner the text message exchange they had about starting inactive players. After receiving the message, the commissioner said that he was fine with people starting weak lineups, just not inactive players. So maybe the commish is more anti-inactive players than he is anti-tanking. Many league members complained about the tanking owner during the last week of the season because it either affected their chances of securing a top draft slot, or their playoff hopes. Some owners are upset that it wasn't caught earlier, because other games where the owner tanked are now in the books.
The commish and vice-commish apparently agreed to create different tie-breakers for this coming season, but never updated the rulebook or disclosed such a change to the rest of the league. Even so, the commish still thought that he was perfectly within his rights to implement the unposted order now. He is really concerned with the integrity of the league.
But as of right now, there is no rule against tanking, the league has never discussed tanking, and the tanking owner thought it was fine based off of previous experiences, his own self-interest, and the text message exchange he had with the commish. The commish doesn't think an anti-tanking rule is needed, nor is one needed to tell people that they must only start active players each week.
Considering all of this, do you think the commissioner made a mistake? Was it wrong for him to unilaterally implement any "corrective" measures after dues were paid? Please explain below.