I am glad to read some really sensible and clever talking about the Q issue. I have seen numberless people flamed in forums because of it. Always found it disgraceful, everyone does what they can.
The first thing my vet told me when I asked about quarantine was: "do you have two completely separate buildings where to keep the birds? No? Then forget about it, they will breath the same air".
As you know I have a constant stream of birds coming and going ;in a perfect world I would have a quarantine heated shed. In reality I keep the newbies out of the bird room and pray. I refuse to turn down rescues because of some quarantine rules I can't enforce.
It will probably cost me dearly one day but I don't feel like I, and many others, have an alternative.

Very well clarified.... thanks...

Very good points from your vet Barbara. I suppose having them 2 rooms away in a very small house isn't quarantining at all. Hmm... I'll keep this in mind.