Yeah, the admin post at the start of the spike was talking about needing to stagger new registrants, presumably to avoid an eternal September like scenario where the community permanently changes character.
If this is the case, makes perfect sense. I may be a newbie to Lemmy, but looking around the best case scenario imo is a whole bunch of instances, both existing and new, take the load. That way each instance gets to decide what they want their own communities to look like.