Cho moved to New Zealand with her parents when she was 8 and quickly become one of the top amateur golfers in the country.
A source told the Herald that Cho, 17, who now plays under her Korean name of Jeongmin, was keen to continue playing under the New Zealand flag but her parents wanted to switch her allegiance to Korea.
"She still has family back in Auckland and I know she intends to come back here around Christmas time after she's had her first go of it in Korea," Thorpe said. "Long term there's nothing to say she won't play under the New Zealand flag again."
Cho won the NZ National Amateur in 2009, beating Ko in the final.
The following year she won the Australian Strokeplay Championship, becoming the youngest to accomplish that feat, before losing in the final of the Australian Amateur Championship, a matchplay event.
By March last year she had established herself as the No 1-ranked amateur in the world before Ko overhauled her.
Now she will attempt to make her fortune on the professional circuit.
Nobody will begrudge her that, but it once more raises the question of how many resources NZ Golf should pour into Korean-born players without guarantees of professional allegiance.
When Sharon Ahn did something similar in 2007, her decision was met with dismay in golfing quarters. Peter Williams, who became a director at NZ Golf Inc, wrote a column in the Herald on Sunday castigating her.
"Sharon Ahn has exploited this country and is ungrateful for the benefits she's had ... She was granted citizenship with help from the former Women's Golf New Zealand, making her eligible for national teams where she was part of the taxpayer-funded, high-performance programme which paid for coaching and tournament expenses ..."
It's an argument that doesn't sit well with Thorpe.
"Once a person is a New Zealander and a citizen of New Zealand, they're entitled to as much support as any other New Zealander is," he said.
The practice of "using" New Zealand before recommitting to their birthplace was not widespread and he cited the example of Danny Lee continuing to play professionally as a New Zealander as an example.
Thorpe said Cho had communicated with NZ Golf and they were not blindsided by the move.
There will be some anxiety as to the future movements of Ko. She is rated even higher than Cho, becoming the youngest player to win a professional golf tour event at the New South Wales Open in January.
At this week's Herald Future Stars awards ceremony, Ko said she was proud to wear the silver fern on her chest - a positive indicator for future allegiance, perhaps.
