Does “a non-zero chance” mean ‘more than zero’?

YES

non zero Oxford English Dictionary

‘an extremely small but non-zero chance’

Your question:

Is this phrasing peculiar to American speakers or do British speakers use this expression too?

I hear and use this In AmE frequently. My sense is to imply a minuscule chance, a slim chance, a small chance etc...

Here are some usages recently in AmE news/magazines:

“Here’s a pretty incredible fact: There is a non-zero chance that Donald Trump isn’t paying any taxes,” Clinton tweeted, just minutes after releasing her own returns. Time Aug 11, 2016

and

If he starts treating your mother in a way that suggests a potential for abuse, you should absolutely intervene, but there’s a non-zero chance that he’s just happily dating an older woman. Slate Jun 27, 2016

and

So it’s important to check as soon as possible with your local Social Security office to see if you do quality for a non-zero excess spousal benefit. Forbes Jan 2015

And to your question:

Is the author right? Am I the only person who could misinterpret this phrasing?

There may be different senses of 'non-zero chances' in Ame and BrE.

Does “a non-zero chance” mean ‘more than zero’?

YES

non zero Oxford English Dictionary

‘an extremely small but non-zero chance’

Your question:

Is this phrasing peculiar to American speakers or do British speakers use this expression too?

I hear and use this In AmE frequently. My sense is to imply a minuscule chance, a slim chance, a small chance etc...

Here are some usages recently in AmE news/magazines:

“Here’s a pretty incredible fact: There is a non-zero chance that Donald Trump isn’t paying any taxes,” Clinton tweeted, just minutes after releasing her own returns. Time Aug 11, 2016

and

If he starts treating your mother in a way that suggests a potential for abuse, you should absolutely intervene, but there’s a non-zero chance that he’s just happily dating an older woman. Slate Jun 27, 2016

and

So it’s important to check as soon as possible with your local Social Security office to see if you do quality for a non-zero excess spousal benefit. Forbes Jan 2015

And here are BrE usages in the same sense I am supporting:

Economics, Uncertainty and European Football: Trends in Competitive Balance "For CB, each competitor in a match must really have a significant (i.e. non-zero) chance of winning."

and

A 2014 study of chess experts, including Carlsen, shows that they consistently attribute a modest – but non-zero – contribution of chance factors to game outcomes. The Guardian Sept 2016

In summary, it is used by both AmE and BrE speakers in the same sense, probably more predominately in the U.S.

non zero Oxford English Dictionary

‘an extremely small but non-zero chance’

Your question:

Is this phrasing peculiar to American speakers or do British speakers use this expression too?

I hear and use this In AmE frequently. My sense is to imply a minuscule chance, a slim chance, a small chance etc...

Here are some usages recently in AmE news/magazines:

“Here’s a pretty incredible fact: There is a non-zero chance that Donald Trump isn’t paying any taxes,” Clinton tweeted, just minutes after releasing her own returns. Time Aug 11, 2016

and

If he starts treating your mother in a way that suggests a potential for abuse, you should absolutely intervene, but there’s a non-zero chance that he’s just happily dating an older woman. Slate Jun 27, 2016

and

So it’s important to check as soon as possible with your local Social Security office to see if you do quality for a non-zero excess spousal benefit. Forbes Jan 2015

And to your question:

Is the author right? Am I the only person who could misinterpret this phrasing?

There may be different senses of 'non-zero chances' in Ame and BrE.

Does “a non-zero chance” mean ‘more than zero’?

YES

non zero Oxford English Dictionary

‘an extremely small but non-zero chance’

Your question:

Is this phrasing peculiar to American speakers or do British speakers use this expression too?

I hear and use this In AmE frequently. My sense is to imply a minuscule chance, a slim chance, a small chance etc...

Here are some usages recently in AmE news/magazines:

“Here’s a pretty incredible fact: There is a non-zero chance that Donald Trump isn’t paying any taxes,” Clinton tweeted, just minutes after releasing her own returns. Time Aug 11, 2016

and

If he starts treating your mother in a way that suggests a potential for abuse, you should absolutely intervene, but there’s a non-zero chance that he’s just happily dating an older woman. Slate Jun 27, 2016

and

So it’s important to check as soon as possible with your local Social Security office to see if you do quality for a non-zero excess spousal benefit. Forbes Jan 2015

And to your question:

Is the author right? Am I the only person who could misinterpret this phrasing?

There may be different senses of 'non-zero chances' in Ame and BrE.