All my wallet.dats have no password. However, the internal hard disk where the "live" one is located is encrypted, and so are the offline storage devices where I have my "cold" wallet.dat.
I have known about the feature to encrypt your wallet.dat in Bitcoin Core for a long time, but never dared to do it. It feels like I will become one of those who forgot their password, even if I store it in multiple text documents on those redundant, encrypted, offline backups. I've had text files randomly get garbled many times for seemingly no reason. And it just makes my skin crawl to think of the possibility that I will one day have a wallet.dat but not be able to ever access it!
Plus, if I encrypt the "live" one, I can say "good bye" to any automation through the RPC API, which is obviously a requirement to run a Bitcoin-accepting service.
But the cold one? I feel extremely scared of it flying through my network cable away from my control. I wish I would dare to encrypt it, but I just don't. It's too scary. I'm already more than scared enough that my backup disks will fail or that I will forget the password to decrypt those! Or that they are all seized and broken into with their quantum computers.
I've spent a ridiculous amount of time worrying and thinking about my security, especially as the Bitcoin value has increased so much. Still, it feels like I'm not at all safe enough and that it's not even possible to be secure without going to such ridiculous lengths that life becomes one long ordeal.
And I don't even own lots of BTC. I can imagine how paranoid people with like 100 or 1,000 BTC feel now...