Oh, I don't care about SEO on this subdomain. Primarily because the sales process is offline.
But this thread has me thinking. If I have a link pointing to my site from thousands of library sites (Europe, Asia, Middle East, and North America - some schools as well) and if I can dictate the anchor text I might have missed some very important SEO pay-dirt.
I'm now considering moving the login for new library/school clients to my consumer sales site to a /libraries/ or /education/ directory.