I do agree that the altitude must be taken seriously. I've gotten sick. That's why I did write to camp the night before near the trailhead, at 9,000/10,000, and to be okay with NOT going over the pass on day one. Maybe that's enough to acclimate, maybe not. If you feel terrible when you wake up for day one, don't hike, go into Bishop and get a steak at the Bowling Alley. If you feel terrible while hiking on day one, turnaround. But for most people, probably, with that one night's sleep at altitude the day before the hike and a slow first day, they will be okay.

We're talking pretty much about the same altitude situation as going to a ski resort in Colorado.

The thing is, I want even the beginner to experience spectacular mountain scenery so in the USA, that usually means hiking at 10,000, above the tree line.