Which is a possible consequence for violating a zero-tolerance school policy?

Due to it being zero tolerance it will be harsh. In or out of school suspension, and being expelled are possible consequences

Detention, inhouse, suspension or even getting expelled could be a result for violating such a rule.

Explanation:

Rules, such as dress code rule, are not as serious and are most likely to result in detention if you're dress coded too many times. For schools below high school, not paying class fees or fundraiser money could result in inhouse. Other violations or misbehavior can get you suspended. Rules that are zero-tolerance are rules like no weapons in school which, if violated, result in expelling the violator.