No proof but always better to have it and not need it then need it and not have it
No need in general but if the kid looks older, they may ask for proof of age but normally they dont do.
What I heard Children of 2 years old or younger are allowed to enter the Park for free (no ticket needed).
For 2 yrs and under I don't think you need to provide any proof , but it's always good to hold one , just in case
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