There is an expectation of privacy when using the bathroom though. There isn't when using a company issued computer, your employeer controls all the software on it, controls the network traffic - why would anyone have an expectation that what they use it for remains private? It's like there's no expectation of privacy when using an industrial lathe - it's meant for a specific purpose, if you use it for private purposes while at work, you shouldn't be expecting that to remain hidden from your employeer.

If I take a personal note using a company-issued pen, must that be disclosed to my employer?

It's not black and white, and many people will have some expectation of privacy when using company-provided equipment.

Whether there is an expectation of privacy in toilet or on the computer is culture dependent.

> expectation of privacy

US law is irrelevant outside the US

Who mentioned US law?

You.