The Chrome password cache is stored encrypted.
On Linux by using gnome-keyring or the kde kwallet (see the announcement)
On Windows with your Windows logon credentials (similar to Internet Explorer's password cache).
On MacOsX by using the Keychain Access (see the help)
So, on disk the passwords are stored safely, and you can simply:
Avoid to give people access to an unlocked user session.
If someone wants to borrow your laptop, hit:
Ctrl+Alt+L (on Linux)
Win+L (on Windows)
and let them fast-user-switch to a guest profile (on certain Gnome systems or MacOsX) or their own profile (If they have one).
Instead of a built-in guest account, obviously you can also simply create a standard user account on your machine, named e.g.
Forrest Gump. If anyone wants to use the computer, they can use the Forrest Gump account. "My account is my account, and i'm not telling anyone my password."