The headmasters' and Headmistresses' Conference (HMC) would never have been as vulgar as to boo or heckle Dame Suzi Leather, even if her organisation is threatening to remove their schools' charitable status.
But when the chair of the Charity Commission braved the annual gathering of Britain's most prestigious private schools, she was openly laughed at for insisting that her quango's public benefit tests were not fixated on bursaries.
Dame Suzi had attempted to calm the heads by announcing that schools and other charities would have up to five years to improve, provided they showed "year-on-year" improvements.
"We recognise developing partnership activities or building up a bursaries fund will take time," she said. "We also recognise that in the current economic climate it is more difficult. We know you can't pull a rabbit out of the hat."
Some of the toughest criticism came from the head of one of the first schools to pass the test - a test Dame Suzi insisted was not "passfail".
Chris Ray, high master of Manchester Grammar, said he was glad his school had invested heavily in bursaries because the Charity Commission's judgment suggested that the many other types of work it did with the community would not have counted on their own. This was deeply dispiriting for staff, who might wonder why they bothered.
"It's like having your head banged against a brick wall," he said.
The commission published its findings on the first five independent schools to receive the public benefit test earlier this year, failing two - St Anselm's in Derbyshire and Highfield Priory in Preston - for not providing enough bursaries for needy pupils. Both will decide next week whether to accept the judgements or reject them, which could lead to a legal battle.
Dame Suzi insisted no formula could show whether schools were providing sufficient bursaries, and that other activities were considered.
"Indirect benefits could count on their own, providing there was enough of them," she said - sparking laughter from the heads who had just heard the lengthy, yet apparently insufficient, list from Manchester Grammar.
Confrontation had been expected before the start of the conference in Liverpool attended by heads from nearly all of the HMC's 250 member schools.
Andrew Grant, HMC chairman and head of St Albans school in Hertfordshire, compared the commission's actions to Henry VIII's dissolution of the monasteries.
"The threat that currently underlies the Charity Commission's guidance is the well-tried medieval one of confiscation of land and property, and it looks no less crude under the rose of Labour than it did under the rose of the Tudor," he said.
Mr Grant added that parents who paid for private education were so stigmatised that they were made to feel their choice was "tantamount to treason".
In response, Dame Suzi called for constructive dialogue between the Charity Commission and HMC, rather than "exchanging soundbites through megaphones".
`Sit A-levels early'
The chair of the exams watchdog Ofqual has suggested teenagers sit A- levels a week early so those whose papers are re-marked do not miss their university choice.
Kathleen Tattersall's comments at the HMC this week came in response to a comment piece by Geoff Lucas, HMC secretary, in The TES last month.
Mr Lucas had warned that many of the thousand or so teenagers whose papers are remarked missed out on places through no fault of their own, branding it a `national scandal'.
Ms Tattersall agreed it was unacceptable. `How bad can it be for a student to be disappointed with their results one day, to be elated by their appeal, and then disappointed again when they lose their university place?'