That was the question posed in a Sydney courtroom after a Supreme Court judge was urged to discharge a young female juror for allegedly flirting with three gang members on trial.

In two decisions canvassing a range of allegedly flirtatious behaviour in courtrooms, including smiling and hair flicking, Justice Peter Hamill considered applications for the juror to be discharged from a lengthy trial involving senior Brothers for Life members.

The prosecution raised concerns the juror had been smiling at Farhad Qaumi, 34, and his brothers Mumtaz, 31, and Jamil, 24, who were accused of conspiring in 2013 to murder Bankstown chapter leader Mohammed Hamzy.

The men were found guilty on November 11 and on Tuesday Justice Hamill lifted suppression orders over his decisions in June and August, which ultimately led to the discharge of the smiling juror.

Justice Hamill noted there had been "at least two previous occasions" where a juror has been discharged in NSW because of inappropriate behaviour, including a District Court case in which "the evidence supported a finding that the behaviour of the juror was considered to be flirtatious".

"It involved smiling, nodding and flicking of the juror's hair," Justice Hamill said.

In this case, Justice Hamill scrutinised in-court CCTV footage after the prosecution noted apparently flirtatious behaviour between the accused and "two or three members of the jury".

A senior solicitor from the Director of Public Prosecutions took notes of the wordless exchanges, which included "lady in white hooded jumper, third from right [in jury box] smiling and looking at Farhad Qaumi".

The solicitor also recorded "girl third from right back biting right index finger and looking at Qaumis", along with "Farhad pushing tongue against side of mouth and looking at girls".

The young woman was also overheard telling other jurors – including one who had been discharged from the jury – "I looked over and he smiled at me so I smiled back".

But John Stratton, SC, for Farhad Qaumi, submitted: "For all we know, the juror might have been referring to the boy she met at the local dance hall last Saturday night."

Justice Hamill noted a co-accused unrelated to the brothers, who was not a recipient of the juror's attentions, did not oppose the application for the juror to be discharged on the grounds there was a "reasonable apprehension of bias".

The barrister for the co-accused "rather poetically ... posed the question 'what is in a smile?' and answered 'it is a nothingness', but went on to submit that the problem is that the smiling [in this case] is 'persistent'," Justice Hamill said.

Justice Hamill accepted the "interactions" between the juror and the accused had taken place on a number of occasions.

However, in his earlier decision he said the objective observer "would take into account that the juror .... appears to be very young and, perhaps, a little bit silly" and her behaviour "may be the result of nervousness or shyness".

He refused to discharge the woman from the jury and noted it would not be appropriate to discharge a juror for "scowling" at an accused from time to time.

But Justice Hamill reconsidered his decision when the prosecution made a second application in August.

In discharging the juror, he noted her behaviour was "persistent and furtive" and "went on for at least two months".

He was "particularly conscious" of the position of the co-accused, who had not received the juror's smiles.

Justice Hamill concluded "a fair-minded observer ... might conclude that the juror might not bring an impartial mind" to the case.