That is certainly one of the disadvantages of having fixed dates for budgets. It removes discretion on the part of the government as to the timing of tabling the budget; however, even if a government has discretion, as governments have had for the last several decades, there's always a possibility of unforeseen events happening that throw a monkey wrench into the fiscal planning of the government.
When the Minister of Finance tabled her budget in April, the invasion of Ukraine was already behind us, but there could be other events happening in the next couple of days that would severely affect the fiscal planning of the government. There's always the possibility of affecting the government's finances, and that's why the government always has a possibility of tabling an update if it's deemed necessary.
As we saw in the distant past—for example, when September 11, 2001, happened—the government tabled a budget in December that was outside of the normal cycle. There's always that possibility of tabling an update.