I think you're being overly harsh on the Brumbies MST. They don't get much of a say in when games are to be televised. Timing is mostly due to SANZAR requirements for TV matches. SANZAR wanted a Friday evening game. Apparently the Brums asked for a Sunday afternoon game, but it looks to have been rejected.
Maybe, but first question would be why GIO is booked out on the Saturday by the NRL, the same date that a Brumbies home QF would be held?
That is the key issue here; all the other issues are a by-product of that fact.
Every year the Brumbies, Raiders, other ground users and GIO sit down to agree to a booking schedule. So this was a known potential issue from before the start of the season
Simple booking screw-up by the Brumbies!
We all knew that there were 2xSA games due to the conference system, so the Brumbies really painted themselves in to a corner only having Friday night available. I also believe the SA team playing in NZ would prefer a Friday night game due to travel.
Either way, its another incident that has pissed off supporters and will hurt the bank balance.