One thing to consider before thinking the cruiselines are taking advantage of families is capacity. Coast Guard regulations have a capacity on each ship. Every child onboard, if substantially discounted is one less adult at a higher fare. Purely from a business perspective that would mean either less revenue per sailing or higher adult rates to make up that revenue. Also adults typically buy a few drinks, many spend a few sheckles in the casino and other areas that help with revenue and as a result keep overall fares low. Some lines are very children friendly with most programs and policies, some are not. One tip, if you're planning a trip and will need cabins for more than double occupancy plan and book very early if posible. The earlier you book, generally the lower 3rd and 4th passenger rates will be. Especially if planning for peak periods (anytime kids are out of school). Everything in the industry is based on availability. As it shrink the price climbs. During paek periods availability on tripl and quad cabins goes quickly.