Well I suppose you could argue that if one partner is doing something that the other partner doesn't like or disapproves of then that has potential to escalate into a volatile relationship, so some caution ought to be exercised in the issuing of a certificate.Unless someone can provide a good answer without going into the realms of fantasy, what does it matter if they dont like them in the house?
If they have no cert and no access, then no problem?
One FEO told me that the domestic atmosphere that they sense as soon as they walk into a home is the greatest deciding factor.