In my personal view, option 1 is almost strictly better. Option 2 is never as simple as "only allow actual human beings access" because determining who's a human is hard. In practice, it means putting a barrier in front of the website that makes it harder for EVERYONE to access it: gathering personal data, CAPTCHAs, paywalls, etc.
http://mollywhite.net/micro/entry/fighting-bots-is-fighting-humans