UserID and multiple Accounts

General questions
1

I was reading about multuidevice, login/logout during visit etc here: https://matomo.org/faq/reports/set-up-user-id-tracking-in-matomo/

However, it does not cover how is multu-account handled?
For example, user browses few pages unlogged, then logs ingo account ID 1, logs out and logs into account ID 2.

2

The superuser sets the IPs which you need to be excluded. The rest just views the data.