I'm very surprised that you can't @mention people or CC, anyone after an incident has been created if you are a Requestor or Service Task User. I'd love to see this function added to portal users.
I agree, as an admin I get this question a lot from our users as the feature would help promote important email notifications to agents.
Found a feature request, highly recommend upvoting it if you like it. Their product teams actually keep a close eye on those.
thwack.solarwinds.com/.../allow-service-task-users-and-requestors-to-mention-and-add-a-cc-after-an-incident-has-been-created