The risk really isn’t worth it. All a referral does is guarantee that your resume gets read. That’s it. It’s more of a recruiting thing than a vetting thing.
And it’s easy to find out. During the behavioral they might ask how you know your referrer and what drew you to apply. HR might also ask the referrer about the referred candidate and their history.
During the application, there is a line in the fine print that says if you knowingly provide false information, your application is going to be rejected. I would say that passing off a referral you got online and, in terms with the referral agreement conditions, that implies you personally know them. I would say that’s knowingly providing false information. So if HR finds out, you’re never getting a job here and the referrer is in deep water with them for trying to take $5000 for free.