Thats the “unspoken” general expectation. Even some fine schedules, have 1-10 over as a $0 fine. See pennsylvania:
https://www.penndot.gov/TravelInPA/Safety/TrafficSafetyAndDr...
However, some draconian towns like Collegedale, TN which advertise no crime statistic in 20-30 years feed off the college kids and give them 5mph over tickets all day long.
Its not necessarily about changing behavior, but there is a balance to be striken between the letter of the law and the spirit of the law.