From Bowerman and the Men of Oregon:
"But before [the Tahoe Olympic Trials] could begin, there was a terrible meeting...the distance runners at the LA trials might not be able to place in the top six at altitude, let alone the top three. If we wanted the most competitive team, we'd send the top three from Tahoe, but if we wanted to be fair we'd honor the promise made to the winners of the LA Trials and take them no matter what. It was an awful bind and it was only settled when LA 1500-meter champion Dave Patrick rose and said, 'If I can't make the top three here I don't deserve to go.'"
It's a tough break, for sure, but don't jump on Bowerman or the USOC for trying to send the best possible team to Mexico City.
Aside from being at altitude, the Tahoe trials were ran on the same schedule as the Olympic games, so 3 heats for the 1500 rather than two at L.A. Who cares who runs the fastest time in a prelim? World Championships are races, not time
trials.
It is a pity that the exact nature of the qualifying was not laid out earlier, but in the end the Tahoe trials were a much better qualifier for Mexico City.