They don't appear to be rate limiting their API that allows enumeration of first and last names. Also,

We’d also like to address the claim of a “leaked” list of Coinbase emails and user names. This list (the size of which is less than one half of one percent of Coinbase users) was not the result of a data breach at Coinbase.

There are 2,040 names on the leaked list. Fun fact: that means there are about 408,000 Coinbase users total.