Very legit point! That is a concern that some of our prospective users do share. What they do in that case is vouch for ones who they know are looking out or can benefit from vouching (eg. folks who struggle at DS/algo interviews etc).
On the "no recruiter mails", I just realised that it might be confusing. What I meant that just because you vouch for someone, it doesn't mean that they will get bombarded with spammy recruiter mails. I think that means object is the person you are voucher for and subject is contingency and in-house recruiters at tech companies.
A headsup in case you are not using official LinkedIn API, LinkedIn is nuclear on browser extensions operating on its site and would even ban the users using the extension[1]. They actively scan for browser extensions and regularly update their blacklist.
On the "no recruiter mails", I just realised that it might be confusing. What I meant that just because you vouch for someone, it doesn't mean that they will get bombarded with spammy recruiter mails. I think that means object is the person you are voucher for and subject is contingency and in-house recruiters at tech companies.