You didn't mention whether it was a cash account or a margin account, or if there's an exception for fully paid securities. If it's a margin account, that is indeed how it works for non-fully paid securities. If it's a cash account, or there's no exception for fully paid securities, regulators will probably not view that agreement favorably. You can file a complaint at https://www.sec.gov/complaint/tipscomplaint.shtml. In my experience, they actually read and act on complaints. (Well, at least small easy to investigate ones... ones requiring a lot of investigatory work like the Madoff case are a different story.) The relevant regulation is 17 CFR §240.15c3-3, paragraphs b(1), b(3), and b(3)ii. (http://www.ecfr.gov/cgi-bin/text-idx?SID=f07570958d348a3f75d...)
> even if that clause was in your contract, they have to notify you whenever they lend your shares. That right to notification CANNOT be waived in the agreement.
Just read my brokers agreement - they can indeed lend my shares without notifying me for any purpose.