I don't know, I am on the fence on this one. I can see where you wouldn't want to give someone a complete article - and that would work but I do hear what others are saying about not giving out free samples. I've always given samples with the up front information what they are reading is previously published work. If anything else was asked for, then it would not be a free sample. It makes me nervous for reasons on being scammed to hand out something for free.
Don't write free samples. I stopped doing this a long time ago. I wrote a free sample for a client, then used the sample later on for another client. Well, the previous client had published the article without paying for it or letting me know it would be published so it looked like I was plagiarizing. I was angry and so was my client. Fortunately, the situation was understood and my reputation was not harmed. Since then, I have refused free samples. I have samples available. A client should be able to use those to tell whether to hire me.
Freebie, assigned writing sample never. Perhaps an outline of an approach or concept but never, ever something that can be used without further work. This type of thing also happens with full-time writing jobs. Years ago, a software company interviewed just about every Technical Writer in San Antonio. The interviewer, who claimed to not know anything about interviewing, asked for our critique of their current materials to show her our skills. As if by magic, weeks later, they "discovered" that they had someone in-house who could do the job. They got an hour or so of free consulting services by each of the city's top writers for free. What a great scam! What made the whole thing even more revolting is that the company made software for lawyers and was staffed almost exclusively by lawyers. They knew exactly what they were doing just like many of these free sample seekers do.
It's pretty simple to defend yourself from the sample article con: 1. You keep it, and use it as a sample article for someone else. They don't have to keep it, but it is a sample of your writing style and skills. 2. You submit it to article directories as your own, so the copy scape is messed up
That's an interesting idea, post it somewhere on the Internet before submitting it to the prospective client - diminish it's value as original content even before they can steal it. I like it.