The legal definition of what constitutes mischief is far different than the ordinary use of the term in every day language. People can get charged for mischief in very serious circumstances where significant and malicious damage is done to property, Also for damage to data more in line with the present times. A confusion in the language arising from the separate charge of public mischief is natural considering that that offence usually involves the misleading of a police officer investigating what could be a mischief offence to property and the sentencing is quite distinct.
The definition is so all encompassing that I once had an impaired charge reduced to a mischief charge as the crown was prepared to accept my categorization of the offence as rendering property, namely a motor vehicle, dangerous contrary to section 430 (1) (b) of the Criminal Code as the more appropriate charge than impaired driving in that case.
Mischief to property has been interpreted in many forms. Putting a poster on a post may not be mischief while the courts have held that a picketer standing with others may be guilty of the offence. Even a loud party has been held to attract criminal sanction as such interferes with the enjoyment of property as well as being a nuisance in the civil realm.
The spectrum of the section is so wide as to cover the breaking of a light bulb with intention to altering data to desecrating a cemetery to damaging cultural property however that is defined. The penalties can range the whole range from discharges through to multiple years in the penitentiary. If charged anywhere along this line, you need expert legal assistance.