At Dunedin District Court this week, Judge Kevin Phillips said a conviction would end any possibility of a professional rugby career for amateur colts player McDowall.
Instead, he granted a discharge without conviction and ordered him to pay $3000 in emotional harm reparation.
Judge Phillips reminded McDowall that alcohol was known to have ruined the careers of international cricketers and rugby players.
Commenting on the case, University of Auckland law professor Dr Bill Hodge was impressed by defence counsel David Robinson's "pretty brilliant" advice.
Ahead of sentencing, a remorseful McDowall had sworn off the booze, completed 100 hours of voluntary community work and offered to pay reparation to his victim.
But Dr Hodge warned that there should not be separate laws for sportspeople. "If this was an apprentice welder or potential builder, I would hope the judge would've gone about it the same way," he said.
"There should not be a get-out-of-jail-free card because you're a present or future potential sportsman."
Dr Chris Gallavin, dean of law at University of Canterbury, said sportspeople were the "bread and butter for applications to discharge" in NZ.
Judges must weigh up whether the actual penalty would far outweigh the gravity of the case, he said.
"That will always lend itself to people who are in special positions - whether they are sportsmen and women, Maori King's sons, or people in positions of special responsibility," Dr Gallavin said.
"Builders or plumbers are unlikely to lose their job or be in a position of never being able to be builders or plumbers ever again over something like this. Whereas with a sportsman or woman a conviction could destroy their career."
A spokesman at the Dunedin police district prosecutions office yesterday said he would assess whether an appeal would be mounted.
John Freeland, senior president of Taieri Rugby Football Club, where McDowall plays for its premier colts side, said the incident should be a lesson for all young people.
"It doesn't matter what career or code they follow, if they put themselves in the eyes of the law, they all should face the risk of not being able to travel overseas or follow their professional aspirations," he said.
"We have a number of talented boys at our club - there's a number of talented boys around town. I don't think Riley is an exception by any stretch of the imagination."
Otago Rugby Football Union general manager Richard Kinley wasn't in a position to comment about McDowall's future career. But the fact that McDowall had made the under-19 representative team meant he was "obviously not a bad player".
- additional reporting Otago Daily Times
No conviction
• In 2012, an ex-All Black had a conviction of assaulting his son overturned on appeal, with a High Court judge ruling he was at risk of losing employment from speaking engagements overseas.
• Last year, Blues player Francis Saili was discharged without conviction for driving while his licence was suspended. Blues coach Sir John Kirwan told the court a criminal record could affect his future selection.
• Polocrosse player Casey Anne Mullany was last year originally granted name suppression and discharged without conviction - after being convicted of drink-driving - on the basis it could impede her ability to compete overseas. The decision was overturned on appeal.
• In June, international freestyle snowboarder Ben James Stewart, 21, escaped conviction for cannabis offences, with a judge saying he hoped he goes on to "realise your potential".
