Oh, that's why my ears were burning.
For what it's worth, I don't hesitate to use beta readers here at AW. I select from people I 'know' here, who have been around for some time (years, usually), whose critiques here seem insightful, who write or at least are well read in my genre.
While we all think our concept is worthy of theft, it's even rarer than theft of the finished work. Writing a novel is hard work, and slow. Making the sale is long odds, too--too long to be worth months of daily effort. ('2% of completed novels sell' is a figure I see tossed around unchallenged, but it's never clear whether that's first drafts, or polished and repped by agents, or what.) How many people are not only dishonest but also work that hard for odds of 49 to 1 that it will never pay off?
Maryn, who didn't mean to scare you