I looked at the code and it seems webmasters can simply put their own ratings and fake reviews to be displayed in search engine rankings...is that ok with Google?
Obviously, the webmaster simply inputted the review manually in there but it shows up in SERPS, very easy to game...
Is there a way to pull the genuine Google places ranking reviews for that?
Yes, it is easy to abuse with fake reviews. And that's not OK with Google. It violates their terms in that you should not deceive your users, and the offending sites and pages might be penalized.
In general, you should probably not manually copy reviews from Google Places or other sites and use those reviews in the microdata as it seems to violate the guidelines for review snippets:
Ratings must be sourced directly from users
And the guidelines for crititics reviews:
Only include critic reviews that have been directly produced by your site, not reviews from third- party sites or syndicated reviews.
