[usrusr]

“New cars are so much cleaner than your old car" is a cross-brand claim that is important for the whole industry. Any damage to that claim would increase replacement cycles.

The best case scenario for telling on competitors would be a larger fraction of a smaller market, worse outcomes would involve a similar or smaller fraction of an even smaller market (after symmetric response accusations hitting your own brand). You don't sell Marlboros by pointing out that smoking Lucky Strike might cause cancer.