nomis5 - 6:20 pm on Dec 21, 2011 (gmt 0)
I haven't heard of any Google safeguards against false reveiwes in Rich Snippets. Anything more specific about what they are?
It seems to me that one review is enough to generate those attention grabbing stars, no more is required. And don't forget the picture that can appear as well, all courtesy of Rich Snippets - the picture gives far more SERPS real estate to an entry than the stars do. Both is best though.