One widely used method to foster team working is to let people solicit peer feedback. However, peer feedback can also backfire. 

What is the value of peer review feedback system?

Without peer review feedbacks, some employees may not provide necessary support that their peers needed to complete the business priority of the organization. In order to get good peer review feedbacks, employees are motivated to collaborate with their peers. When the reviews are evidence based and for each piece of feedback, there is a constructive suggestion on improvements. 

Can peer reviews be abused?

Yes, peer reviews can be abused by unethical employees. People can lie about their peers' performance to gain an upper hand in the review. For example, a team has two members, A and B, they have a fixed budget for bonus. A is a high performer, instead of working hard, B may choose to lie about A's performance so that B may get a little bit more bonus without much extra work. 

How can peer review abuse be prevented? 

Just like book reviews on Amazon, buyer/seller reviews on Ebay, peer review should also allow the owner to leave comments on his review. In the above case, for example, when B leaves a comment "A's code is not well designed". A can leave a comment "The design documentation for feature X is located at Y, which has been reviewed by the team". This can largely mitigate unfair peer reviews.