One thing I like about Google's process is that we take you to lunch, but explicitly tell you "this is off the record, no feedback will be submitted. Ask any questions you want, or just chill out and eat."
And people fall for that?
I've definitely seen the lunch interviewer pulled into the conversation. When the process isn't supremely formal, lines get blurred. Being paranoid is probably a smart thing to do.
Except for some smart alecks who would put in "Candidate held fork in left hand, was neat eater" I never saw anything beyond "n/a" or similar non-feedback. Most often I would see a savvy recruiter pair up the lunch with the referrer so they could catch up with their friend and it would act as the 'sell' part of the interview slate.
He joked that "Well, if you punch a hole in the wall I might write something". Other than that we just talked about hacking game consoles & Chromebooks & breaking out of Chrome's sandbox to reach the OS from javascript.
This is a functional and smart practice.
When I did lunches, I would make it clear that they could ask any type of questions or just hang out.
Honestly, I would rather find out that being Mormon and having 2 kids at age 25 is a problem sooner rather than later. In my last job, the fact that I don't drink came up in the interview. It want because they had a problem with it. Rather, they wanted to ask me if I was comfortable with the somewhat alcohol focused culture of the company. These are important parts of the recruiting process, at least to me.
FYI, none of the things you mentioned is (in itself) something that a company can (legally) choose to factor into their hiring decision. Experienced recruiters and/or interviewers will avoid those topics entirely because, while they may be able to ask questions that happen to reveal that information indirectly, they're risk-averse, and they'd rather not open themselves up to a lawsuit.
That said, this is one of the reasons I get uncomfortable when people use the term "culture fit" - it's not a bad idea in general, but it can oftentimes be a euphemism (perhaps even unconsciously) for inadvertent discrimination. (Why is Joe not a good culture fit? Is it because his hobbies include taking care of his two kids, rather than rock climbing or bar hopping, or something else that the rest of the 20-something office enjoys doing?)
> In my last job, the fact that I don't drink came up in the interview....they wanted to ask me if I was comfortable with the somewhat alcohol focused culture of the company.
I can sympathize with this.
I once had an interview where I asked why my interviewer (an early employee) left his previous job to join this company. He said that he felt "a strong culture fit". When I asked why, he said, "Well, the founder was drinking a 40 while he interviewed me". I waited for him to finish his explanation, then realized that that was the extent of it. I asked him to tell me more about the culture, and he made more some general statements, but was unable to give any other concrete examples.
The only thing that an early employee at that company could say to sell me on the company was that the founder drinks during job interviews. I'm glad I dodged that bullet early.
This is true, but it is something that you can factor into your employment decision. That is, deciding whether or not you want to be employed by a certain company.
If we make a decision not to hire someone and we asked that question and they wanted to stir up trouble, they could try to build a case based on us asking that question. Would they succeed? Probably not. But it would cost the company a lot more than just not asking the question.
It kind of sucks, because there are lots of good schools in the area, but we couldn't bring them up unless the candidate did first.
In my team's case, it's generally the person who did the candidate's phone interview who takes them to lunch when they come on-site, but I don't know if that's a common thing.