In the worst case scenario, RotR is only processing 1,500 people per hour.Another important thing to note (I don't think today is one of the days), but when guests from Starcruiser are in Batuu, they are prioritized to get on Rise when it comes back up, before LL, and then standby.
There are 200 rooms at the Halcyon, so, let's say 500 people come over from there.
So, if they all showed up at once and were prioritized, that would only be a 20 minute delay for the ride.
But, the guests of the Halcyon show up one shuttle at a time over the course of several hours. Their attendance wouldn't be noticed by any guest normally. Unless, the ride was down and then came back up, and they notified all 500 Halcyon guests to rush over to the ride at once and gave them priority. And again, that would only be a 20 minute delay.