Thus, the warrant I am applying for would permit
    law enforcement personnel to, with respect to any device     
    that appears to have a biometric sensor and falls within 
    the scope of the warrant: (1) depress BERMUDEZ’s thumb- 
    and/or fingers on the device(s); and (2) hold the 
    device(s) in front of BERMUDEZ’s face with his or her eyes 
    open to activate the facial-, iris-, and/or retina- 
    recognition feature.

These documents read like an instruction manual of what not to do (use biometrics in this case). Upmost of which is commit a crime, but if criminals knew to read these docs first, they'd be much harder to catch i suppose.

[1]: https://www.justice.gov/opa/page/file/1318666/download