The Constitutional Court on Thursday debated whether children could be held liable for defamation for doing something that they thought was a joke.

The court heard the final leg of the first case of children being sued for defamation when it sat in Johannesburg on Thursday.

In argument peppered with giggles from the packed public gallery and occasional reminiscences of their own school days by lawyers, the court was told that three former Hoërskool Waterkloof schoolboys were just being immature when they doctored a picture of two gay bodybuilders with the visages of their principal and deputy principal.

"They didn't think their deeds through," submitted Gilbert Marcus for Hennie le Roux, Christian Gildenhuys and Reinhardt Janse van Rensburg who are challenging the R45 000 damages awarded to their former vice principal Louis Dey.

He accepted that Dey was hurt and that the Constitution allowed the right to choose to be gay or straight.

But he submitted that children were frequently impulsive, without the intellectual development of an adult.

They were all under 18 at the time and have said that they had not intended to harm anyone or damage the integrity and dignity of Dey.

In 2006 then 15-year-old Le Roux cobbled the picture together on his computer and sent it to a friend via cellphone.

This was then passed on to Gildenhuys. It was eventually printed out, and Janse van Rensburg pinned it on to the school notice board.

Dey sued them and the damages award was upheld in the Supreme Court of Appeal.

The court was on Thursday asked to consider whether children can be held liable for statements or actions such as these.

Marcus then shared his school nickname with the court saying: "My nickname was carcass - not because I was a slab of meat, but because it rhymes with Marcus".

He suggested that maybe people had forgotten what "typical schoolboy" behaviour was.

But the judges fired a range of questions at him to establish whether accepting such behaviour was actually allowing the pupils to undermine school staff leading to everything "breaking down".

They also wanted to know why Dey and his superior Christo Bekker had been targeted and not their parents or dominee.

The Freedom of Expression Institute submitted that children should be allowed greater latitude than adults as they experiment with expression and that they have a right to be more careless in their expressive acts.

It said that it was difficult in an open and democratic society to draw the line between what was and what was not humorous.

"So does that mean children get greater freedom of expression than adults," asked deputy chief justice Dikgang Moseneke.

"Special considerations may apply to those experimenting with expression," replied advocate AD Stein, adding that while they are doing that they may not understand the consequences.

But Moseneke persisted: "Do you want the court to send the message to all teenagers in schools that it is very well to stick the head of your principal on a naked body?"

Stein said that the boys did it in a "rush of blood", which they regretted.

"These children did not understand that what they were doing was unlawful in the way that we understand it."