Which is both good and bad. A star party is about (at least) 2 things -- getting to dark skies, and socializing with other astronomy nerds. So while one can go to LSA any day (not just adjacent to Calstar) a core point of having "official" dates is to be there when a lot of others are, to show off your gear, look through others, meet friends, camp, share food etc. But we want to do it under clear, dark skies. I dropped the AirBNB but will come up tomorrow probably to GSSP, though Sunday night looks iffy, Monday and Tuesday look like they will be good (maybe even great on Tuesday night.)
As a person of flexible schedule, I would find it an advantage if the principle was, "a few days before the event, we might move the event 1-3 days, still retaining a couple days of the original schedule for those who are not of flexible schedule." Of course that requires all sorts of things that can be moved on short notice, which not every event will have, but Calstar generally does. But it is not enough for me to be able to arrive earlier or stay later to get the clear skies, it is not Calstar unless lots of others are also doing that, it is just an OI. Of course, at LSA it need not be anything official. One person could say, "based on the forecast, I am showing up 2 days late and staying 2 days later if others also would like to do that" and others could then chime in and a movement could begin. That is the plus of the county park. Of course it's ideal if the gods cooperate and the scheduled days are clear days, and everybody's a winner, but an event where far fewer people come because that isn't true isn't desired. An event where half the people come on days 1-2-3-4 and the other half come on 3-4-5-6 and everybody is there on 3-4 is the best result from that situation. (And the very flexible come 1-2-3-4-5-6.)