These aren't necessarily announced the moment they happen on JP (as normally they overlap Urgent/Emergency Quests as their schedule is usually more packed), but they do post notices throughout the day that say that there will be a casino boost at x time. Usually there's also one shortly before.

I haven't seen the announcement system used yet on NA for anything other than Maintenance and Urgent Quest announcements, this would be a great way to utilize it especially because JP already does this.

It's a good idea. Casino is pretty much dead and announced boosts in more populated blocks would really get it moving. It would be nice to see a lot of people in the casino playing together at once rather than 1 person on slot machines- no one touching mesetan. and a couple people playing blacknyack and MAYBE roulette.

I wanted to come in with an example of what they do for an event.

When the events are spread out JP will usually announce once around 6 hours before or so, and then another time 30 minutes before, with something like this:

"Attention to all players: We will be holding an event. "Lillipan Roulette" will be boosted with higher double chance rates! This event will be held from 1:00 JST to 3:00 JST."

I don't remember if they do it in the middle of the event too saying there's an event going right now, but usually it ends up overlapping with an EQ so they don't announce it the moment it starts anyways.

That said, considering casino is way more popular in NA than it is in JP I 100% think this is a good move and will raise casino participation a lot