"You understand and agree that all Collateral may be pledged and repledged and hypothecated and rehypothecated or otherwise used by Morgan Stanley."

1. If you signed an agreement with your broker that says they can loan out your shares, then YOU HAVE GIVEN CONSENT! At some brokers, you can remove that consent (but some of them don't make it particularly easy).

2. There are a few small changes when they loan out your shares, most notably dividends are not qualified anymore (and have an associated higher tax rate), and you can't vote those shares (because someone else owns them at the moment). If you use a broker that does this to you without informing you, well, I'd suggest you switch brokers. In all my 40+ years of investing, I've never once experienced a dividend that became non-qualified due to being loaned out and I never once experienced owning a stock that I couldn't vote my shares due to it being loaned out. This is at 4 large brokers over the years. Maybe they only lend out non-dividend shares and maybe they cancel the loan (and have the shares returned to them) during the annual voting period?

3. At this point I only have two of my securities loaned out, one earning a relatively high rate, and one earning a low rate. But even the low rate one is still adding some income to the normal dividend. If the broker would be lending them out anyway, I may as well share some of that interest! One of them in a margin account, the other in a tax-deferred account.