Occupy trio's surrender begs the question: how severely should they be punished?

They could be let off with a slap on the wrist or be thrown behind bars for years. As the trio who came up with the Occupy Central civil disobedience idea turn themselves in to the police today, legal eagles differ over the severity of their likely punishment.

Ex-director of public prosecutions Grenville Cross raised the possibility of a five-year jail term, the maximum for organising an unauthorised assembly under the Public Order Ordinance.

But Eric Cheung Tat-ming, a University of Hong Kong principal law lecturer, said the facts did not support convicting Benny Tai Yiu-ting, Dr Chan Kin-man and the Reverend Chu Yiu-ming of organising such an assembly. If they were just participants in an unauthorised assembly - something Tai said yesterday they were prepared to admit to - a fine would be the norm, Cheung said.

HKU law professor Simon Young said the trio's trip to the police station "will be like walking into a lion's den". "They may think they will only face minor charges … but the joint enterprise principle could result in more serious criminal liability."

Cross said the more serious offence of organising, with the five-year maximum, was possible, depending on what they intended to confess. "This maximum shows that, in the most serious cases, the legislature clearly intended that offenders can receive condign punishment," Cross told the Post. "I do not think that anyone could seriously deny that the unauthorised assemblies we have seen on our streets over the past two months represent, in terms of scale, duration and consequences, a worst-possible-case scenario."

He noted that the trio did not hide themselves, meaning the police could have arrested them earlier but decided not to.

"If the trio hope that by surrendering themselves they can somehow force the hands of the authorities, they may be sorely mistaken," Cross said.