But this is not normal. The prices are normally twice than the regular price are sold.
You're of course correct - my example was in 2001, which was Gerard Mortier's last year as Intendant, and as I understand it, some longtime subscribers boycotted the Ariadne performances because of the "scandalous" production of Die Fledermaus a few days before in the Felsenreitschule (the person who was selling did have quite a number of tickets).
In 2005, the year of the Netrebko/Villazon "Traviata", people were offering €5000,- for a single ticket