The question was part of three questions posed by the judge in the case as the initial possible panel was selected.
Australian-born Harris, 84, of Berkshire, is accused of indecently assaulting four girls, the youngest of whom was seven or eight and the oldest 19, between 1968 and 1986, which he denies.
The evidence before them dates between 1968 and 1986 and "includes events" in both counties, said Mr Justice Sweeney.
He told the potential jurors the trial will last until June 27 at the latest.
Mr Harris was at the court, but only his wife Alwen sat in the public gallery as proceedings began.
With 12 jurors required, potential members were asked whether they have any connection with the case or with anyone who is involved in it.
They were also asked if they have close friends who live in Australia or New Zealand or are going to be visiting the countries before the end of June and "with whom you are likely to be in contact during the course of the trial?"
Potential jurors were also questioned about whether there is a compelling reason requiring them to be excused. The judge stressed that inconvenience was not a valid reason.
He told them: "A fair trial is the right of all in this country. To state the obvious, the role of the jury is a vitally important one in ensuring the fulfilment of that right."