The foreground app bundle-ID will be collected according to the schedule(s) configured for the data-collection rule. 

Alert rule(s) can be set up to check if the foreground app is not the desired one or is in a supposedly blacklisted app.  However, the most frequent collection interval of 2 minutes may not be sufficient to cover ALL cases if the foreground apps actually got changed in between two collected samples.

I never used that for a report but i assume you have to do this following way:

1. Put the data collection rule in place for the desired devices/groups, so the data will end up in the DB
2. Create/Add a custom report to the reports which is showing this data as build in the report
   • This can be scheduled and automatically send out via mail (if a mail account was added to your Mobicontrol instance in the global settings (Services > SMTP)

To create this report, you need an external tool (a link to it is inside of Mobicontrol when you click on "import report" but has only a trial license) and you need access to your DB to know which field(s) you must use and how they are named etc..