Hi,
Am not a blind advocate of active voice myself and believe that passive voice is not a taboo on technical writing. But then, in some companies such as one I worked for before translation costs were a major (and pointless) drain, we have been tending to take active voice pretty seriously.
There are two ways passive voice affects translation:
One is, of course, the increased word count, like why say something in seven words when you can say it in five? I believe the current rate for translation is $1 per word (or is it more?).
Second, passive voice is not quite amenable to translation and does
raise kinks in translation. Grammar and syntax are not really the same across languages....
Did you know, in Sanskrit, you can say "I stand" in passive voice. Now how would you translate it exactly into English: "It was stood by me?"
So, I think we could allow a deviation from active voice when describing system reponses etc so long as we are not translating stuff to other languages, and be a bit strict with passive voice if we know our docs are going to be translated.