I run a 4-year old, contract, money league. Due to the presence of contracts and cash, some trades can get pretty odd. For example, I recently traded Beckett for Micah Owings and cash. I couldn't keep Beckett or afford to resign him, and whoever got him was going to have to pay out the nose to keep him by giving up cash and their Franchise Player. Because we have deals like this, and to make sure that vetoes were only happening for deals that absolutely needed to be vetoed, the league put in these rules:
First, we made vetoing a deal extraordinarily difficult. The trade has to be vetoed with a 2-to-1 supermajority against it, and
there needs to be at least 4 nay votes. That second provision makes it hard for a couple guys to band up and run out to derail trades by a particular owner.
Second, we actually put in the rules a statement that reads, "Each owner is strongly encouraged to veto only when collusion is suspected and for no other reason." Obviously, that doesn't prevent anything, but at least everyone knows the league's stand on the topic.
Third, we make all league voting 100% anonymous. Even the commish doesn't know how owners vote, and we specifically prevent our arbitration process from trying to determine how each owner voted. You would think that the anonymity would make it easy for someone to vote against a trade, but the anonymity comes with a benefit. If you don't know who voted against your trade, you can't cast a retaliatory vote later. The anonymity of the system contains emotions and prevents petty squabbles from arising.
In the end, the rules end up turning our veto system into less of a trade evaluation system and more of a rules
evaluation system. In 4 years, we've vetoed exactly one trade. An owner out of contention was trading players to another owner in contention with the strict agreement that the players be traded back after the playoffs. We called it a "rental" trade, and it went down in a ball of flames for obvious reasons. Since then, we've had one other trade that really pushed the rules, but it wasn't illegal. It passed, and we cleaned up the rules later.
There are some guys here at the Cafe that are in my league: daullaz, RyanK, DaQ, kellythemick, BigH0rt. If you want a second opinion on the quality of these rules, go ahead an PM them. They'll always speak their mind objectively.
Oh, and one last bit of advice: Get good owners. They make all the difference.