I was on vacation in Halifax so I attended a CPL match between HFX Wanderers and Cavalry FC.  It was cool to see that the CR and both ARs were women officiating a men's professional game.  However, I noticed the 4th Official sat for most of the game unless something was going on (a substitution, talking to a coach, incident on the field, etc).  Is this common practice in Canada?  Here in the US, I never sit down as a 4th Official.