Everybody does. Undoubtedly required. I doubt you are required to give honest answers although you might have a hard time challenging their advice if you lied about your assets.
I'm in the process of converting our retirement and joint accounts now. I posted my reason for converting our accounts in post #39 (Vanguard provides SIPC insurance coverage only on Brokerage accounts). I had been considering doing it for a while, but am in the process of doing Roth conversions this year, and originally wanted to hold off until completed.
I called and asked if conversion could be done individually on each account. They told me yes (three separate people in different conversations). You can't... When you click the "transition" button (located on the right, above each retirement account - Legacy view), it brings up all of your Retirement accounts (we have access to each other's accounts, along with joint account). The joint account did not come up. You must do all retirement accounts. The conversion for my wife's account did not take and was told to call. Turns out she must convert from her own sign in. Since she has access to my accounts, she had to process all mine as well. Hers went through and mine failed on her sign-in... Guess you might call this weak IT set up.
You have to answer the "(What's your Liquid Assets)", and "(What's your Net Worth)", for all accounts or it won't proceed. You are also asked what is your goal with your investments. These are Brokerage boilerplate type requirements according to Vanguard. I chose the first (lowest amounts) answer for assets and net worth (we are Flagship), and chose "preservation" for goals. I considered it to be the correct selection for ("prefer not to answer").
I called Vanguard about the Joint account (transition button inactive) and was sent a link to convert it to Brokerage. It's a manual process where I filled out the paperwork, and mailed it off to El Paso, TX for processing. It's done, but took awhile..
I am also converting our Joint Account into Individual accounts to split the amount to stay under the SIPC $500K max per each investment account. This was easy to do by setting up the Individual Accounts and waiting for them to do an in-kind split of Joint Acct (not a taxable event). I called them and they gave me instructions.
Will finish the Roth conversion when advantageous. It's a little different than the Legacy Account, as it transfers over "as it is" in the IRA now. If you don't have that fund in your Roth - it creates it for you. I was able to select where it went in Legacy...
You 1st get a confirmation of the Brokerage account set up, and then will get a notice of transaction when they move the funds from Legacy to Brokerage.
Hope this helps those asking about the process.