I was told exactly this yesterday flying YVR-LHR. I had a confimred M class U/G and my friend, who has no status, was on a H fare. rang up 4 days out, no I space so on the waitlist and his booking was linked to mine. At checkin got on the u/g list and at the lounge was told by the desk agent that he would have no chance of an u/g as he would be the last to be considered as he has no status. This is a crap rule