Yes, you can add an eventhandler to an element in your repeating table. In the sample code below I check on deletes. In your case you will use eventObj.Operation = "Insert"
Sub XXXX_OnBeforeChange(eventObj)
If eventObj.IsUndoRedo = false AND eventObj.Operation = "Delete" Then
'do something
'eventObj.ReturnStatus = false
End If
End Sub
Note, there are OnValidate, OnBeforeChange and OnAfterChange events. Read the help in InfoPath Script editor for more information. Note the OnValidate and OnBeforeChange have the DOM read-only and you cannot make any changes to other fields within this event. If you are adding logic that will update another element on insert, use the OnAfterChange event.
Jason
http://www.k2distillery.com/