I had thought of this as something that someone might do on an airline that they rarely flew and for which it wasn't worth buying a lounge membership.

(For example, an AA flyer on what they anticipate would be their only UA roundtrip of the year. If one assumes a connecting flight, it would cost $200 per person to buy passes to the RCC at each stop on the itin.)

It hadn't occurred to me that someone would do it on an airline they regularly flew even if the airline didn't care. There's some point after which the hassle of doing this would outweigh the cost of just joining your regular airline's lounge.