Third country nationals who are transiting through Canada into the United States are obliged to do that, but Canadian citizens are not. Partly it's a question of volume.
But with respect to the case of individual freedom, we have a certain trade-off. If you provide information and you make known who you are, you get through the border more quickly. As people, we make decisions all the time. If you have a card at Shoppers Drug Mart, you get discounts on things in exchange for data. You've made that decision. You're not obligated to have one, but you've made that decision.
To me, I think most people who are crossing the border want to get across more quickly, so they will make those trade-offs. It is also important to note, however, that when the beyond the border negotiations took place, there was, included in the core of the agreement, a privacy framework that did involve the Privacy Commissioner. At the time, she looked very closely at this and found that the framework was fine.