That is the perfect question. It should be the norm for long term investments.
I don’t know when it was but the large banks/brokers lobbied and made it against the law for companies to tell (or even suggest) there investor to DRS.
The only down side I know of is that when selling, shares have to be paired with a buyer, which isn’t instant (may even take a couple days).
But the up side is they cannot lend your shares to short them against you. Also, if the price was to go brrrrrrrrr and be in the hundreds or more (cough cough millions) brokers can sell your shares for you, at any price, and say it was for your safety as the stock was volatile.
Yes! Or more accurately “lend” them to someone who will.
Even if you have a broker that promises not to there is minimal regulation to stop them and if they get caught the fine is a (small) fraction of the money they make on that transaction (which is just a cost of doing business). I believe this was shown in r/superstonk just by someone looking at the sec filing.