Looking at their yelp page, they do have 5 star reviews, and they also have 1 star reviews. There are few filtered reviews, but they aren't universally high ratings or anything, and I think Yelp does filter out users with a single review that is 5 stars because they are usually fake.
I'm also sure that a restaurant feels that recent reviews should be weighted heavily, almost exclusively, and that those two star reviews from last year should be ignored.
I'm also sure that a restaurant feels that recent reviews should be weighted heavily, almost exclusively, and that those two star reviews from last year should be ignored.