Gonna speak from my experiences as a tournament host here, and would like to note that all these thoughts are my own and definitely do not speak for all tournament hosts. Also my bad if this reads really badly, it's midnight on a Friday and I'm exhausted lol...
In a lot of circumstances (albeit less so lately), I find myself hosting tournaments in a tier that I do not play or really know much about. I really just host tournaments because I, for the most part, like hosting tournaments. When I am hosting for 1v1, which I do know enough about, I tend to just make a second post reminding players that [insert pokemon here] got banned or something.
If people in charge of tiers want to tell me what got banned, I'd gladly make posts about them in the thread reminding players. I generally don't like putting it in the title for visual reasons, as 1v1 Global Cup III - Round 4 (Second Phase) (Replays Required) (Ogerpon-Hearthflame Banned) is a title I would not wish on any person on this site.
Anyways, if y'all want to make it policy for hosts to give out a reminder, that would be fine. Idk how this is for other tournament hosts, but if someone wants a reminder to go out about tiering action and wants to ping / dm me to ask me to put out some sort of reminder, I'd gladly do so without second thought. I also think doing a second post is better because it's overall more visible than just putting it in the OP, but doing both is even more visibility for players.
But please for the love of god don't make 1v1 Global Cup III - Round 4 (Second Phase) (Replays Required) (Ogerpon-Hearthflame Banned) a tournament round title.....