Does remQ also stop the bogus/erroneous business transaction?

No: alerts and the case management are reporting tools. No transaction is stopped or business data altered by the remQ software. remQ has read-only access to business data.

And Yes: since release remQ 2.0 auto-reaction methods can be defined that are triggered when an alert is created, approved, or rejected. This requires to define auto-reaction methods and is not the default behavior of the software but can be enabled.