I'm in the view they do. I've been offering a pretty generous fee of $2000 if someone is referred that I can help land and about 1/3 of my 2008 placements came via such referrals. My average placement is $20k, so I'm offering about 1/10 of the fee. I also get referrals where the fee isn't offered- the $2k referral is usually more pro-active in nature via linkedin and email marketing.
Yes, folks refer candidates as they like and respect my work- but I'm more then willing to offer the fee as I believe it's an added bonus especially as a lot of contingent firm recruiters can't offer the fee as they're working for someone else.
Our entire website ReferQuest.com is based on referral fees and, believe me, they work! In fact, we would like to invite all of you to be test users of the new site, and let us know what you think firstname.lastname@example.org! It's free to post or refer. No spam, no scam. Thank you.