A record 28 amendments have been submitted to next weekend's conference of the Scottish Secondary Teachers' Association in response to proposals from a special committee on disruptive pupils.
Headteacher members are particularly unhappy that the committee is at risk of binding their hands by suggesting that parents should "sign a binding contract to support good order and discipline".
The union's headteachers' advisory panel, chaired by Douglas Campbell, head of Bell Baxter High in Cupar, wants that phrase deleted in favour of parents being asked to "acknowledge their responsibility".
Heads are also wary about the restrictive implications of the word "contract" and will insist on "home-school agreement". The report receives a fairer wind, however, in its proposals for clear strategies to be developed before excluded pupils are readmitted.
There is no opposition to a radical suggestion, which illustrates the depth of teacher emotion on the subject, that heads should be prepared to refer cases of indiscipline to the children's panel "if teaching staff recommend this approach".