If that's the case then it's clear standards go a long way down in the 23rd century. Even here in the 21st century people are rightfully holding heads of state accountable for deaths under their watch. Not going to cite specifics but you need look no further than recent news.Probably. Look at all the times Worf killed someone under circumstances that were perfectly legal under Klingon law and all Picard or Sisko could do was yell at him and write him up for insubordination, at most.
Kirk agreed to take part in a Vulcan wedding, Kirk was warned that the proceedings would take place under Vulcan law, and he still agreed, even after Spock told him he was ignorant of critical information. Sure, no one told him flat out that the fight was to the death, but Spock begging T'Pau to forbid it should've suggested it was going to be more than a little friendly tussling like he assumed. Kirk would've been killed though his own negligence.
My take is different and I think if Kirk had actually died, while T'Pau might avoid prison time the Federation Council would vote to expel Vulcan from the Federation unless compensation was made to Kirk's family (in whatever form that takes in a possibly moneyless society) and new Vulcan laws put in place to ensure such a thing never happens again.
T'Pau may look down on the Federation Council to refuse a seat on it, but her planet still ultimately must answer to them if they want to stay Federation members.