Resolution:
To test the size of the events table, issue the command
SELECTcount( *) FROM EVENTS ;

This data is historical; this table can be truncated if the data is not being used for reports.

In TIBCO InConcert 6.0 and above Events can also turned off.  See the Batch Registry documentation on "Update Event Type".  Also in IC_HOME/utils there is a file ev-clr-all-record.btg of batch registry commands to clear all events.  

You do not need to have the event turned on for a trigger to fire on that event.