Sorry! My post re: BA v OW equivalent status cards was a bit terse and didn't explain why:

1. The visitors using the Lounge are actually a cost to the airline - what that cost actually is, I can't say, but our accountants will have a good idea. BA First, Club, Premiers / Golds / Silvers and their guests costs are absorbed by BA because the financial advantages of past, present and future business repays the airline handsomely! OW carriers, however, are recharged as per the Alliance Agreement for their cardholders who use the lounges. (So, Globaliser, each time you enter the lounge, QF receives a bill!) Therefore, if we allow extra guests not covered by the agreement, we would be looking after them for nothing (and the vast majority of OW cardholders using BA lounges are travelling BA for the cheap short-haul add-on leg of a longer journey).

2. You must also remember that the majority BA customers who own a OW card do so because they earn 100% of all mileage - even on cheap fares. BA Cardholders receive 100% of mileage only on the high yield fares and receive only 25% on cheaper fares. The allowing of an extra guest is a small trade-off, but a trade-off nonetheless!