Yes, I got to that part, and they asked for your username and Password for my Etrade acct (they claimed it will not be shared with anyone..lol). I canceled right there.
I have no idea who is behind these companies or what security they have in place. Never give out your Username/PW to anyone.
I looked at some of those programs and its either discounts for their products or giving T-shirts. I guess they want to peak into your acct to see if you own the shares. Has to be a better why then that.
I believe NSAV already knows where your shares are held, how many, dates of purchase, and account number. That holds true for all companies you hold shares in.