Events Duplicated in Group Events Block

I ran into a problem where events displayed in the "Group events" block were duplicated several times. I resolved the problem by making one small change to og_calendar_block:

		// Modification 2007-05-23 - Added "DISTICT" in order to avoid duplicates: 
        $sql = "SELECT DISTINCT e.nid FROM {event} e INNER JOIN {node} n ON n.nid = e.nid WHERE e.event_start >= %d ORDER BY e.event_start";

I simply added "DISTINCT" to the $sql, and that resolved the problem.

My question is: Was "DISTINCT" not put in originally by design, and if so, what are the ramifications of me adding it? If not, then could it be added to the code to avoid this sort of problem in the future?

Thanks!