I am curious what other established recruiters think about being asked for references by prospective customers.  It's a bit rare for me, since I've been in the business so long and have usually been highly recommended before the initial contact, but in some cases, prospects haven't heard about my work and want to speak to someone I've made a placement with.

The problem of imposing on someone else's time is an issue, though.  I've made 17 placements at one firm, but am still cautious about volunteering the CEO's name, knowing how busy he is.  A recent placement for another company was a PhD with 170 patents, so they would probably be an excellent reference, but I feel a little uncomfortable about the imposition, there.

What about a candidate as a reference?  The fellow with 300 patents I got a $million sign-on bonus has asked me to conduct searches at 14% for him (gee, thanks!), so I won't go there.  The CEO of the company where I placed two top execs who sold the company for $200 million has also moved on, and I haven't been in touch with him for years.  

I used to have a written signed reference from a billionaire who was COO of a client where I made 10 retained placements, but I didn't save it (who knew?) and it would be odd to ask him for a reference since it's been 20+ years, although we are still connected on LinkedIn.

What have other recruiter's experiences been?