I think this has been discussed before, (some time ago) but as of Difinitus' new post, I'm curious. Is having an account on a device and sharing the device with a friend or family member considered "sharing" if only the owner knows the password and others just use the device with it already logged? Also, what is giving an account to someone considered? If someone doesn't play anymore and they give their account to their friend by having them change the password and register their own email it would just be their account.
Are you asking if it's account sharing if they physically use the device (but not play the game) while you are "logged in" to CH? No.
If you are referring to this person actually playing on your account while using your device:
"Would they do something bad on my account?" Unlikely since you know this person and are standing right next to them.
"Could they do something to my account?" Yes.
The goal of my post was to educate players about protecting their account from unwanted access. No, you shouldn't give your friend your device with your account logged in to play because they
could steal your account or delete an item. The best way to protect your stuff is to never give your account details to another person, but that also includes letting them play on your account on your device.
Now, I don't really want to get into answering "what if..." scenarios about the Terms of Service but I will answer your last question: Yes, giving your account details to another person, even if you quit, is considered account sharing.