A quick Google search says Mayweather's net worth is $450m, so if anything this like more of a Jay-Z-owning-the-Nets situation than having a real ownership stake.
Famous minority owners are good publicity, but does anybody really care about them after the fact? No outcry for Will Smith to sell his minority stake in the Sixers (though that would be kinda funny).
With someone like Mayweather, I could see some fuss initially, some protests/outcry, but similar to Chauncey Billups and the Blazers, where it doesn't seem like the outrage was loud or long enough to really impact anything.
For real ownership issues, I have a hard time seeing anything but a loud objection from the players stopping anything (like with Donald Sterling or Rush Limbaugh's bid).