The easier you can make your service to use, the more likely I'll use it. This definitely needed a solution, and the best route would be one with minimal or no impact on UX.
If you're not a robot then captcha is rarely more than an extra click these days if you use recaptcha.
One extra click can make a lot of difference for someone performing that action 100s of times a day!
You'd just add it to the account creation.
Not my experience; I usually have to go though several rounds of select all the road signs. I'm not sure on what basis they decide to haste some users vs others.