If it sounds 'great', everything is ok?

Of course we will try to overcomplicate this. But I think that’s a fair rule of thumb to simplify the 1-million-variable complexity of vinyl setups: if is sounds really good, it probably isn’t too far off the mark on anything. Maaaybe VTF and anti-skate can get into "you shouldn’t do that" territory without being overtly audibly bad. But VTF is super easy to check & re-check, and anti-skate should be applied sparingly. 

You might add some conditions, too:

• Does it remain good across the whole record surface, especially inner grooves?
• Does it retain clean playback at loud SPL (exposing feedback and rumble issues), assuming the owner chooses to enjoy those levels? Boy has that one bit me lately lol.

I got a new Fluance RT85 a few years ago that sounded obviously "wrong" on first listen. There was a significant Left / Right imbalance, plus additional sonic problems, almost like the channels were a bit out of phase. Then I looked at the headshell, and the factory-installed Ortofon 2M Blue was clearly mis-aligned in the shell: it had a significant offset angle deviation, when the cantilever was straight. Squaring it in the headshell 100% fixed the sound. I forget if I even bothered to verify alignment on any of my tools lol. It still sounds good to this day.

@eagledriver_22

The Clearaudio magnetic bearing arms are far enough away from the VTF scale that it should not affect the measurement at all. However these arms are extremely sensitive to footfalls (or feedback) and require meticulous isolation to work well - but if you’re concrete slab they should be OK.

Yes, it’s perfectly possible the VTF is actually 2.9g and still sounds good. That might even be smoothing over issues with the magnetic arm (which I’m definitely not a fan of - especially the Concept and Clarify models. If he has a Magnify, that one is a hybrid and I like it much better). 2.9g won’t hurt anything in the immediate short term, but you really do want to verify and adjust that down to 2.0g max.

There are going to be opposing views on the dangers of high VTF. Some would say it's better for the stylus to remain firmly seated in the groove, even at a bit too high a VTF, versus being too light and risking mis-tracking, or even bouncing around in/out of the groove. 

If I found out I'd been running a cartridge at 2.9g for (say) a week by accident, I'd correct it but wouldn't sweat the "what ifs" about whether damage may have occurred. Quite frankly I'm surprised an Ortofon 2M could hit 2.9g without bottoming out, since they're already low riders by nature and have fairly compliant suspensions. 

FWIW Ortofon's high-end MC's are spec'd to track as high as 2.5g or 2.6g, and I think some SPUs may be even beyond that.