There was a really interesting video (can't remember the title) that went into Google's captcha specifically, and found that it really isn't designed to detect bots. It's designed to detect a unique digital fingerprint that can be used by advertisers.

So, you can use a really simple mouse script to click the checkbox automatically with no issue, but as soon as you use a VPN you get served with the photo games. It doesn't care if you're a robot, it cares if you're a valuable ad target.