A senior police officer may declare a place referred to in section 45F to be a designated area only if--
(a) any of the following has occurred at the place in the previous 12 months--(i) at least 1 offence committed by a person armed with a knife or other weapon,(ii) at least 1 serious indictable offence involving violence against a person,(iii) more than 1 offence of possessing a knife or prohibited weapon in a public place or school, andNote--: See the Crimes Act 1900 , Part 3A, Division 2A and the Weapons Prohibition Act 1998 , section 7.
(b) the senior police officer considers the use of hand-held scanners is likely to be effective in detecting or deterring the commission of an offence involving a knife or other weapon, and
(c) the senior police officer has considered--(i) the effect the use of hand-held scanners may have on lawful activity in the area, and(ii) if the place was previously a designated area--whether knives or other weapons were found during the period the place was previously a designated area.