A lot of those RT are expensive LMB food. Several of us years ago checked on the CA events. ...from Doug Hannon, who is widely regarded to be one of the premier authorities on largemouth bass.

This in regards to California largemouth that reach twenty pounds:

"The balloon-like proportions of these fish indicate adaptive specialization at its extreme limits. Just as coyotes have adjusted to susbist on garbage and poodles in the Los Angeles suburbs, California bass have adjusted to feed on stocker rainbows. Staying close to this food source, which has a preferred temperature around 54 degrees F., keeps these bass in the cooler fringes of their environment, which in turn triggers the fat-storing mechanisms of a pre-winter metabolism. As a result, an 18-pound California largemouth is no longer than a 10-pound Tennessee bass, just a heck of a lot fatter". Tracked down several of the state guys who did the transport and stocking. They described the stocking as mostly 1-2 lb. fish, which were upon release immediately ambushed by LMB. With no habitation they guessed that predation was 25% in the first few hours after release.

I do agree that stocking RT in ponds can be a good idea.