I can see the points on both sides. Stealth checks are good for the calves, the bulls don't really need it. Of course, everyone believes himself to be a bull.
I rip my own games, rip them twice and compare the CRCs. I do run them through ABGX360, but I never autofix anything. About a third of my games aren't in the database, anyway. I don't need stealth firmware. Honestly, I'd use Xtreme firmware (my 360s have BenQ drives) and be done with this for good, but I don't think C4E ever corrected it for the disc angle bug, and I'd need to reburn many discs to compensate.
Producing a non-stealth firmware version isn't any riskier than the activate.iso, IMO. And if no one knows whether Microsoft can detect (or infer) using activate.iso, then non-stealth firmware may actually be safer for people who know their rips are good.
If ABGX360 says they're good, I don't need the 360 firmware checking them every time.