To this day, assessing reputational risk isn't part of our mandate when we organize events such as an address to Parliament. The protocol team and the Sergeant-at-Arms's team are more concerned with physical rather than reputational risk.
If we were ever mandated to do this kind of verification, we'd have to evaluate how much time and resources that would require. Our understanding has always been that it was incumbent on the party or group submitting these lists to us to do these background checks beforehand.