If an event has an ARexx script or command associated with it, REMINDERCHECK sends the command or starts the script before it opens the requester for the event. The requester is opened immediately, however (i.e. REMINDERCHECK does not wait for the ARexx script to terminate).
NOTE: In order to get ARexx working, RexxMast must be running at the time REMINDERCHECK is run. Because both these programs are usually launched from WBStartup, you can't be sure which of these will be run first. The only way is simply to try. If ARexx does not seem to work, you have to start RexxMast from your user-startup.
Note also that ARexx does not work if you have the NOAREXX tooltype in your REMINDERCHECK icon.