Australian police now have the ability to “hack into [a suspect's] computers for up to three years without their knowledge.”
Australian legal processes are not my forte, but if this trend continues, that’s one more risk going on with your network: even if their intent is only to read the files accidental changes can happen — especially since hacking attempts are almost by definition a violation of your system’s integrity.
The law apparently applies to “offences punishable by at least seven years’ jail, including … money laundering, hacking, organised theft and corruption.” Setting you up for the possible double whammy of having your records hacked and used against you, but the records you use in your defense being called into question since your system was hacked.