When Events are cloned to another site, the underlying Event Category gets copied along with the date, time, recurrence pattern, venue, tags etc.
Therefore your affiliate group should collaborate before syncing to agree on consistent category names to avoid confusing duplicates and redundancies.
Consider the chart below. Both Affiliate 1 and Affiliate 2 have the categories that mean the same thing but are spelled or expressed differently. When events are synced to the State website, any categories not already present will be created on the State Affiliate's site. Affiliates should agree ahead of time on a category naming convention to avoid this issue.
Affiliates may also want to agree on the same color for the calendar legend as well.