For the league matches, if at all possible, I do think players should announce that they're going to play BEFORE they actually do.

I know it seems like a formality, and it is under normal circumstances. It's also unnecessary if you get a match together on very short notice.

Anyhow, while I don't expect the following situation to happen very often, I think it eventually might happen if games are routinely played without being announced:

Player A claims to have won a match against player B, but player B claims that it wasn't a league match. If the game was announced and played, then there's an actual record on the basis of which the TD can decide to count it or not. If it hasn't been announced, there will be nothing you can do.

Anyhow, I don't expect any of the current participants to get involved in controversies like this. But I suggested this rule in case somewhere down the road we get people who are overly worked up about moving up or down and might get involved in situations like this.

If it's just common practice to announce beforehand whenever possible, then I think it will help to prevent possible future conflicts from arising--if we should get some "difficult" players in the league, as will probably eventually happen if the league becomes an ongoing btp institution. So, I'd just like to get this habit established now as a preventive for future conflicts.