This is the issue of privacy -- and is concerned with keeping everything "open" to an interviewee beforehand.
If you're being "watched" during the interview (through a camera) by other people in a separate room -- do you absolutely want (need) to be aware of this before the interview -- or is it OK if you were told this afterwards?
In my current company... During an interview session -- which is strictly "one interviewer and one interviewee" -- we have 2-3 employees setting in room right next to where the interview is going on -- watching the interview process on a large monitor. These employees then vote (yes/no) for the candidate and the management takes those votes as an input in its decisions.
Now, after all the interviews are complete, all the candidates are taken to the next room. They meet with the company employees and have casual chat about the company, work environment, management, etc. It is there that the employees tell them that they'd watched the interview -- that it went well (even if it didn't) -- and that there was no recording.
This "after interview gathering" with employees makes candidates relaxed and feel friendly -- and (so far) no candidate has showed any concern about the deemed privacy infringement.
Does this sound unacceptable to you?
NOTE : I am asking this ONLY in the context of a "job interview for programmers (and software engineers)". Period. Do not generalize it.
I don't like it. If your team gets to meet the candidate afterwards and you have time when the candidate has left to talk to your team for feedback that should be more than adequate. I don't see how employees watching the interview contributes much, you have to make sure there's a good chance they work well together but this can be gauged post interview in the casual setting.
There's also a conflict of interest, if the candidate is told afterwards and you have not yet received complaints, it is likely this is because they do not want to jeopardise their chances at the job they might need. In actuality they might feel very uncomfortable and awkward.
Also be wary to not turn it into an entertainment style viewing for your workers, it's peoples lives. I'm not saying that's what it is, but it could easily degrade into such ways and that sets a terrible precedent.
I would think it is advisable (fairer and possibly safer) to let the interviewee know before hand that this session is being recorded or observed remotely by a separate team to help your organization make a better hiring decision.
There is certainly precedent for this with proper disclosures in other technology as well as creative organizations. (Walt Disney picked up the voice talent for Snow White by having the auditions piped into his room so that he would not be influenced by the looks of the candidates)
That sounds like a bad idea and I would not participate in it on either side of the table or viewing room. Too Stasi-like for me. So many things can go wrong - this is meant to be an interview - not entertainment or casual viewing.
If you need multiple people involved then have them in the room with you or have them interview one by one.
The whole point of getting feedback is to have interaction. Something is lost on video - and there is not the same anonymity from people's reaction to hiring. There is a group dynamic in the viewing area and people are swayed by others.
BAD IDEA. Drop the practice and stop being lazy.
Show some respect for your potential hires and give them the courtesy of meeting the people who will be evaluating them.
To answer your question, it is unacceptable to me. If they're not open, transparent, and forthcoming during the job interview, just think of the shenanigans that must go on after being hired. No thanks. On to the next interview.