The Transportation Security Administration announced on Wednesday that they are going to be doing more random gate checks at airports from now on. They actually started doing them a few months ago.
The Spokeswoman for TSA, Laura Uselding said "this is not because of any specific threat", but additional measures to help prevent "weapons or other contraband from being passed from an employee to passenger before boarding". "Gate screening is particularly effective at addressing insider threats and serves as a random and unpredictable security layer that, like all TSA's security measures, was developed using a risk-based approach," Uselding said.
The TSA sent letters out to airports last week informing them of the changes.