I haven't found this to be the case as much. Posted a job, got 100 applications, at least 10 had referrals. 10 is manageable for me to sift through but not the win the applicant thought. More than that, I found a colleague had a whole google form process to farm out referrals.
Bonuses. Usually there is no penalty for failed referrals, so the more people they refer, the more likely someone gets hired and sticks around long enough for the bonus.
