Write down their site / password info. They'll never know you have their login data, no access logs or warnings.
Note that the people freaking out the most about this are incredibly uncreative, because they think this is the only way an unattended computer can be powned, usually combined with weird beliefs about "Security" being a boolean value. Obviously, if you have physical access, you stick a keylogger on there, steal the whole DB of passwords at the binary file level, take over the whole operating system, etc. Also for extra comedy the people most likely to be outraged stereotypically have the same password for all saved sites (LOL) so you really only need to write down one password for that user, and also stereotypically its a variation of "1Password" or their kids name, etc.
I didn't know that the chrome://settings/passwords page existed until I read your comment. I actually just checked it out, and when I clicked the "Show" button on the password box, Chrome made me re-authenticate with my Windows password before it would show the password.
I don't know if this is a new feature, only available on Windows, etc., but it seems like this may be less of a concern now.
I did find it weird that I had to re-authenticate with my Windows password and not the password that Chrome is syncing passwords with, but it's better than nothing.
Sites that are heavily automated / packaged / locked down will not be up to date.
I can verify it works fine on linux 44.0.2403.107.
I have access to a 41.0.2272.101 on windows that is extremely heavily locked down and centrally distributed but I don't use that out on the internet, it would be non-trivial to test.
open a tab to chrome://settings/passwords
Click on a saved password and click "show"
Write down their site / password info. They'll never know you have their login data, no access logs or warnings.
Note that the people freaking out the most about this are incredibly uncreative, because they think this is the only way an unattended computer can be powned, usually combined with weird beliefs about "Security" being a boolean value. Obviously, if you have physical access, you stick a keylogger on there, steal the whole DB of passwords at the binary file level, take over the whole operating system, etc. Also for extra comedy the people most likely to be outraged stereotypically have the same password for all saved sites (LOL) so you really only need to write down one password for that user, and also stereotypically its a variation of "1Password" or their kids name, etc.