The gotcha is that from what I understand, there is no rule allowing any of the above. Chicane, practice laps, etc. And like the letter says, it would be unfair to the other teams that brought usable equipment.
The FIA would have been crucified if it had not followed it's own rules, and maybe that was what the 7 teams and Michelin were really hoping for from a political perspective.
I realize it was no grand prix, but the fault lies with the competitors, and equipment suppliers, not the track, or sanctioning body.
And I'm sorry, these are professionals. If you tell them to drive slowly, and they don't, you fire their ass, or get the programmers to slap in a speed limiter.
If I tell someone I am paying 6-8 figures a year to drive my car to go out and lose with dignity, then they better damn well do it. I have no sympathy for any of the 7 teams, or Michelin. They F'd up, and rather than losing with dignity, they took there toys and left. Not very professional IMHO.