Info(“guid”) Always unique?

I am wondering if info(“guid”) is guaranteed to generate a unique number for every user.

The documentation says…
“This string is generated by the operating system and includes the host name, process ID, a time stamp and a counter, which ensures that the ID is unique for the network.”

What if some one is on a different network?

If it is on a different network it is not guaranteed to be unique. It probably will be, but not guaranteed. If you think about it, the laws of physics will tell you that guaranteeing a unique number across the universe is impossible, at least without any communication.