I created a wallet.dat with Bitcoin Core on a new PC. Then I encrypted it with the GUI menu.
When I reloaded that computer, I was shocked to see that Bitcoin Core did NOT ask me to decrypt/unlock the wallet.dat -- it just loaded it right back up. The only indication I got that it was encrypted was that the "Encrypt wallet" menu item was disabled/greyed out. Not even a small text saying: "This wallet is encrypted."
Obviously, this made me feel as if it was not encrypted at all. So, assuming that Bitcoin Core had saved some kind of decryption file on my other computer from which it auto-decrypts it or something, I transferred the wallet.dat over to my current computer, also running Bitcoin Core. Same thing there: the only indication that it's encrypted is that disabled menu item.
Nothing else. I'm able to read the labels and see all the receive addresses and everything. Since the wallet has no actual Bitcoins in it yet, I can't test to make a transaction, but hopefully, at least that will prompt for the decryption passphrase.
Is there something I'm missing? Why isn't encrypting a wallet.dat actually encrypting its data? Is this like that idiotic practice that WinZip/ZIP format used to do where you could see all the files and the filenames but just couldn't read the file contents without the password? I never understood the point of that, and I certainly don't understand the point of Bitcoin's encryption if all it does is prevent you from sending coins away, but still allow you to snoop on the labels and receive addresses and all that.