No, actually. It really doesn't take that many bits of entropy for you to be unable to find any documents in a haystack of entries. My file ID is 45 characters

No, actually. It really doesn't take that many bits of entropy for you to be unable to find any documents in a haystack of entries. My file ID is 45 characters of base-64 encoded string. This is a total entropy of 225 bytes. If there are a quintillion files in google drive (a hundred million files per person who has ever lived), you were loading a million possible files per second, you'd still take several times the expected time to the heat death of the universe to randomly stumble upon one.