I don't have an example to showcase, but I have a general question. If a website provides its data open and free, but to download them you need to fill a captcha, can I use an automatic way to auto fill the questions and download the data I want?
It might be consider illegal. Autofilling captcha is a blackhat toolbox and in most of the cases you should avoid it. The best thing you can do is read the "term of uses" of the site and if you cannot find anything there, then you can always contact with them and ask for a certain reason to send you the data directly.