I heard these stories when I worked in travel a year ago, can't validate the authenticity of the first one (you know what rumours are like), but the second one I got really good mail on.
Short answer: Yes.
The person was involved in an Australian soccer club (not the new A-League, long ago) and was questioned over why bookings made for his "first cousins" were members of the soccer team. His membership was suspended and all points in his account revoked after an investigation.
The other, a platinum member who booked his wife, three kids and "sister-in-law" in business class to the US. (Obviously during the days when you could actually find availability

) The member was quite rude to the consultant during the booking because of the time it took and accidently let slip that the "sister-in-law" was the nanny. The consultant then sent off that little nugget of information to the service centre for investigation who severely rapped Platinum member over the knuckles.
And as for the political correct challenge to same-sex relationship? We are talking the travel industry here, sweetie. :P If the situation is corrupt enough or someone is bored enough, they'll investigate.