Recently, cancelable biometrics, zero-bio, PKI with biometrics, and some related methods have been proposed as remote biometrics. These proposals are discussed in the viewpoint of not forensics but privacy protection. When forensic techniques are abused on the remote biometric authentication systems by third person, he/she can collect information of authentication process, such as stored templates, intermediate calculated data and etc. This situation causes novel privacy issues about excessive collection of information. Therefore, we define "receipt-freeness" of biometric authentication protocol, from the viewpoint of anti-forensics. As a first step for considering requirements for "receipt-freeness" remote biometric protocols, some related works are analyzed about characteristic of "receipt-freeness." As a result, we show the all protocols do not satisfy "receipt-freeness" except a few situations since the servers of these protocols remain some evidence such as transformed biometric data.