People can mention group when mentioning is set to nobody

[Moin]

The documentation says that everyone who can see the group can use the autocomplete. But only when the user is allowed to mention the group members are notified.

@Discourse

Mentioning groups

When users type the “@” key followed by a group’s name in the composer, all visible groups will appear in the autocomplete list. For example, groups like @trust_level_0 will show up by default.

Enabling mentions will notify all members of the group. When a user mentions a group, they will see a confirmation message: