@Michelle it happens frequently.
I tell the clients this; 1 guy denied you entry, and another is now saying "you don't need a waiver". In 5 years when you have a $5000 trip booked to Hawaii, what will you tell them when they stop you again?
I always tell them to go back to the border and ask the same guy "can I have your card or a letter in writing that says I am admissible?" Then suddenly...the story changes. They take the waiver no problem after that because NOW they aren't so sure. If your 100% sure...make it official. If you won't do that, then TAKE THE WAIVER.
For anyone at the border facing this, $585 USD will allow you to know IN WRITING. Homeland Security will not give you a waiver just because you applied. If they do not find you inadmissible, they will send you a September Letter. You will carry that for the rest of your life. If they grant you a waiver....then you NEEDED a waiver.
I forward my phones so that when a client is at the border they can call the office and get me even after hours. I tell them NOT TO LEAVE but to call if the Homeland Security guy tells him this. When I get them on the phone, and ask for their card or a letter, suddenly they completely change their tune.
I am all for a client not needing a waiver and avoiding the $585, but not because 1) The officer THINKS they don't need it 2.) the officer just tells them this because they don't want to be bothered processing the paperwork.
Canadians view the Homeland Security guys as some sort of bastion of honesty and virtue and knowledge. They are just border guards who are giving their OPINION. Sometimes they are correct and trying to be helpful. Sometimes they are well intended and just wrong. And sometimes they are at the end of their shift and want to get rid of you.
If one officer denies you entry, you want a result IN WRITING. That will last you FOREVER. "um, there was this guy, kinda tall with nice brown eyes who told me 6 years ago I didn't need a waiver. Maybe he left a note of something?" That's sheer stupidity.