As far as Q101 is concerned, during its final year on the air before the Merlin takeover, I never heard any pure alt product. Nearly every single song would fit well as a current, recurrent or library track on a standard Active Rock station. The fact the station never bothered changing its panel status doesn't mean much to me. Toward the end, about 90 percent of the playlist was either nu metal, grunge, or guitar-driven modern rock (Bush, Smashing Pumpkins, etc). Pantera even received occasional spins. Not only was the playlist "heavier" than any so-called alternative rock station in the country, it had a heavier texture than the vast majority of active rock panel reporters.
Q101 made a mistake perhaps by not rebranding, and they definitely made a gigantic mistake but not dumping the awful Manno Brothers from PM Drive much sooner than they did. They were still around several months after the station went heavier, and man did they stick out like a sore thumb for reasons that should be obvious to anyone who's had the displeasure of hearing their on-air work.