Two tools sharing a trench coat
User Scanner checks usernames and, separately, emails, across a large site list. It is in this course because it is actively maintained and because it covers both kinds of identifier in one project. That second feature is also the hazard. A username check loads the same family of public profile URLs you already met in Sherlock. An email check talks to account systems, the way Holehe does. One install, two very different legal weathers. You do not get to notice only the sunny one.
Consensus-OSINT vendors a modified copy and tags some email modules as loud when they may notify the account holder: password-reset style traffic, messages, anything that makes a human's phone buzz. Those tags exist so a careful operator can leave them off. This lesson leaves them off. It does not "try loud once on my own email to see the template". Your own inbox is where you notice the mistake. It is not a sandbox for practising the mistake.
For the required walkthrough, stay on username checks, against your handle or pip_tadwell_osint101. Email mode is optional, and only against an address you own. If you cannot see, in the help text, a clear way to keep recovery and notify behaviour off, you skip email mode. You already have a safer explicit switch in the Holehe lesson: holehe -NP, and only -NP. Do not invent a User Scanner equivalent by turning on extra modules "because Holehe was fine".
What "maintained" does and does not buy you
An active project fixes rules faster than a dead one. It does not make today's rules true. User Scanner's list is large (the Consensus snapshot counted it in the thousands of username sites, plus a much smaller set of email modules). Large lists contain fresh rules and rotten ones in the same afternoon. Maintenance is a reason to prefer this project over an abandoned scanner. It is not a reason to skip the browser.
The licence is MIT. Same as Sherlock: fine to use, and not a substitute for platform terms or the Privacy Act.
Where it sits in OSINT101
This is the lesson where it is easiest to enable something you did not mean to enable, because the tool is keen and the help text is long. Read the flags twice. Then run the smallest command that is obviously a username search.
One tool, two personalities. Only the polite one is invited to class. The other one stays in --help, unread and unselected.