in 2016, attendance was 19.300.000 ( 2 parks together)
that's roughly 52.900 visitors inside both parks on average every day
that's 26.450 visitors on average, per park, per day
that's 66% of capacity on average.
so even with *close to capacity* days, it's easy to see that there is still room for a few thousand people, in the current state of the parks
with, let's say, 30 days of 40.000 visitors per park (highly exagerated assumption), and if we draw the average in both parks, that's 2.400.000 guests in 30 days, leaving an average of 25.200 guests per park per day, on the 335 non capacity days (365 - random example of 30 capacity days)
anyway you look at it, 5000 additional guests per park and per day will not make much of a difference on most days. Most days would be below 30.000 guests on a 40.000 capacity cap. Still manageable for anyone.
Days that are aleady busy would be overly busy, and the rest of the year would just be slightly busier.
but nothing to call the cops about
