N.Y.C. Admin. Code § 17-347: § 17-347 Excused behavior.

No dog shall be declared dangerous pursuant to § 17-345 if the threat, injury, or damage caused by such dog was sustained by a person who, at the time, was committing a willful trespass or other tort upon the premises occupied by the owner of the dog, or was tormenting, abusing, or assaulting the dog, or has, in the past, been observed or reported to have tormented, abused or assaulted the dog, or was committing or attempting to commit a crime. Nor shall any dog be declared dangerous if it was responding to pain or injury, or was protecting itself, its kennels, or its offspring. If the trespass is determined to be of an innocent nature, the commissioner may, depending on the circumstances, and in accordance with the procedures set forth in section 17-345, find the dog to be dangerous.