most schools interpret the best practice guide as to mean the actual assessment booklet that you are given out at the start of the course/year (this is why some schools are so anally retentive about students turning up to assessment information nights *cough my school*)... you actually get up to three terms notice in the HSC year for most if not all of your assessments...
a less than 2 week reminder may be a little rude but then you should have know about the assessment months in advance...... even you dont know the content, you would know the topic area so you cant use that argument either (unless your school is slack and doesnt follow the rest of the best practice guide and nominate tasks against topics and broad due dates (usually done by weeks and terms...even though the doc does say specific dates)....