I'll answer, and I'll ask Mr. Dompierre to correct me if I go wrong on this.
If a person does not make their payment by the time it's due, then the CRA, in all likelihood, is going to charge them interest.
Then, I guess, if the person wants to take that up with the CRA, they will have to navigate the system again to get back in contact with CRA and try to say, “Well, wait a minute. You told me I had to pay it on this date, and I paid it on this date, and now you're charging me interest.” They would have to navigate that system all over again—one they perhaps had some frustration navigating in the first place—just to be able to get the original question answered. How that will end up being resolved, I don't know. It wasn't the point of the question, but it would put the individual back to having to try to take up their issue again with CRA.