Any decent internal recruiter has an agreement that if they reached out to you, even if you bypassed them to contact the company, they get credit. And you are probably being contacted through a CRM that automates it for them.

I'd love to see how this is written into the contract. I've worked on the company side with a lot of contingency recruiters and the wording is never broad enough to cover "we talked to them but didn't actually send them to you".

I wouldn't want to hire someone who goes behind the back of the recruiter who did the work to connect the company with a prospective employee. It seems demonstrative of a lack of ethics.

Seems obvious in isolation like that, but the employer probably wouldn’t know you skipped past the recruiter. All they would know is that you came to them direct, and direct hires are a lot cheaper

Depends on the industry, I guess. Recruiters in my industry tend to interact directly with the hiring managers and it would be pretty obvious.