Are you a teacher? My wife is, and last year it was far cheaper for her to take a week off and a paycheck hit than to cruise during the break week. Her district only gives her 2 personal days; the rest are sick days. So she took 2 personal and had to take 3 unpaid, but the cheaper cruise fare more than made up for the difference. Her administration has no problem allowing for unpaid days, though YMMV. Doing it this way and pre-arranging the same sub for the whole week usually works out well for all involved.
Also note that not everybody has the same spring break. I often read about "spring break" on these boards like it's a national holiday, when in reality the weeks can vary widely. Where I grew up (in CT) we had two separate weeks, one in Feb & one in Apr. Here in the Omaha area, we have multiple school districts (literally 7 in the major metro area), and virtually none of their spring breaks line up with each other. This school year, my wife's break is the middle of March; in 2021 they moved it to float with Easter. I teach at a local university, whose spring break does not line up with my wife's at all. And my son goes to school in yet another district, whose break is also completely different. Within our own family, in one city, we have 3 different break weeks.
Point being... while the weeks before/after Easter are likely popular for breaks/travel, it varies widely. So even for though my wife and I work in education, we'll arrange our schedules to go on cheaper cruises and take advantage of the 10% off. If you have no option to do that, I sympathize. Just wanted to share my perspective/experience.