Why I won't write code demos, articles or new talks in your interview process

I'm currently looking for my next challenge, mostly as a Developer Advocate, which means, I started some very interesting discussions, and as a matter of fact, ended some other for different reasons:

the vision of the job didn't fit mine: quite often they are Technical Writer, Technical Support or Sales Engineer roles with a different title;
the company or product was not as interesting (for me) as I thought: you need to be passionate about the products, services and the company to be successful in this job;
I was not comfortable with the hiring process: more on that later, it's basically the main point of this post;
or simply because the hiring manager didn't think I was a good fit for the role or the company, which is totally fine for me. It needs to be a great fit on both sides!

So what about the uncomfortable hiring process? I mentioned some unpleasant experiences, but rarely things that would prevent me from moving forward. Still, there is one thing that doesn't make sense for me: when you ask candidates, during the interview process, to spend personal time building an application or code demo, write an article, create or give a new talk or even, build a plan about one's vision for the next fiscal year... For me, this is wrong on more than one level:

I don't want to sound like Scrooge, but I'm already volunteering: twice per months, I'm mentoring new volunteers at Suicide Action Montréal. What you are asking me to do, if done well, takes time and is not free: people are paying me big bucks as a freelancer to do these and it's why you will give a paycheque to the candidate you'll hire. I hope it's not like this most of the time, but when I discussed this topic in my network, many people told me they got screwed by potential employers who only wanted some free brain juice: some of them even used the work of the candidate they didn't hire...
Interview processes already takes a lot of time without this special request: quite often it's a minimum of 5 interviews (I know, it's crazy) going from 30 to 60 minutes in addition to flying for a full day at the headquarters (so usually 2-3 days in total including flying time). Let's not fool ourselves here: even if I carefully choose where I'm applying, since I'm actively looking for a job, I'm in this process with more than one company at the time. On top of that, knowing that those processes usually range from three to six weeks from the first discussion to the offer, if any; in the meantime, I still need to take contracts: you know, paying bills!
Unless you are looking for someone with no experience, which is not the case here, there is already plenty of my work out there. Maybe it's not exactly about the technology you work with or not even related to your product, but it will give you a great idea on my coding skills or even more important here, my writing style or my public speaking experience.
In my humble opinion, it's also the least effective way to validate the expertise or knowledge of someone. It's easier for a self-learner to search the web, read some documentation or listen to some talks and come up with a plausible blog post. It's the same for public speaking: if you don't get too many questions, you can be the expert on the stage by knowing just enough. You can do it with coding too: as a freelancer I was mostly doing project rescue and I had successfully deliver projects with technologies I've never used before. Don't get me wrong, I never lied to anyone about my knowledge, but I often had to fake it till I made it, until I became good enough. This specific role brings you in positions where you often need to learn new technology or take on new products. It happened to me in all jobs I had and as far as I'm concerned, you should be looking for someone that has the soft skills as the technical parts of the role (your product, technology, framework...) can be learned: which is why I'm applying on Technical Evangelist opportunities where the focus is a technology or product I don't know... but it's a different story.

To be honest, it didn't happen to me often: only twice since I moved to developer relations, as people usually don't go that way with this kind of role, but I've seen the coding thing quite often for Software Engineer jobs (don't get me started about the live coding test). Last time it happened to me, I suggested that the hiring manager have a discussion instead. I think it's way harder to fake knowledge like this and it's a far better way to acknowledge someone's skills. Unfortunately, she didn't go that way, so I withdraw from the process as I'm definitely not a good fit for the company. The thing is, I know the technology and I could have been able to write the article quite easily, but I wanted to stay true to myself (living by the no bullshit policy, whether you like it or not).

I know, it's an important role to fill, with a lot of exposure, so you don't want to invest in someone who won't fit the bill, but by asking candidates requests like these during the interview process, even if the intentions are good, I firmly believe that you may not help yourself...