All other posted comments pretty much sums it up in this situation... both US and Canada border officials towards foreign visitors will recognize any recorded incident as a conviction if a fine was paid despite the type of judgment that was imposed, no matter how minor or major one jurisdiction classified the incident as.
Border officials do not generally recognize record incidents as infractions or misdemeanors as such, but rather as minor or major offenses, and if they are classified as criminal or non criminal.
Having onhand any documentation pertaining to the case will be a big plus, also some real good advice of not disclosing any information to border officials until asked, and when they ask - they are either wanting additional specific details in the case in order to determine permitted entry or denied entry, or testing your answers to what they already know.
For those in unique and fine line situations pertaining to an incident matter on record, I know that Canada border officials will refer a similar related incident in deep question and recognize it as such according to their own criminal statutes of Canadian law upon making a final determination.
I know Alaska does recognize selling booze to a minor as a criminal offense, despite what the ABC does in recruiting young individuals that look much older in order to prey on a busy server, no matter the circumstances.
I am in a much more complicated situation as I got detailed questioned twice and one other recent time upon major scrutiny from Canada border officials (within my last 8 consecutive yearly crossings entering Canada over an incident with US Army officials in 2005) as I had three serious charges pending, which they never pursued nor formally charged me with anything (really blown out of portion), however it is permanently on record under some "special federal file" that no US federal courts of all levels show on file as I looked into it (that's all I could obtain at this point) as no one can even provide a case number at all for me in which is non existent, however Canada officials clearly see the incident on their database showing no result.
The three times when I was asked about the incident, I went into detail when they asked upon the circumstances and stated that I was never charged nor contacted to appear in court....two of the three times when I was asked about the incident they wanted to see some form of documentation stating so, which has been an impossible task when a court system tells you there is no file or record of it.
Needless to say to this day, Canada officials have never denied me entry nor have I been told to leave upon visiting Canada along with numerous crossings, so after the major scrutiny incident with the official at Port Stewart, he pretty much told me he annotated an advisement on my passport that will need some form of documentation stating the incident is not going to be pursued or I could be subjected possible denied entry into Canada - I finally got cleared after two hours and to continue my vacation destination as planned because of the numerous permitted entry crossings into Canada on record.
Best of luck for your wife's situation, my guess on what was posted there is a slight better chance she will be permitted entry than denied, but it is solely on the discretion of the officer and or the supervisor.
