In Disney's case, though, I'm not sure they are under any illusion of price hikes going unnoticed. I'm pretty positive that they know that sites like this one are almost certain to put out articles, brief as they may be, that announce the price hikes. For examples beyond the ticket prices, look at the recent increase in parking fees and the increase in drink prices. Both were discussed here thoroughly. People who don't follow this closely may not notice, but if they're not paying attention, that's their own fault. The information is out there.
Are there companies out there who creep up their prices quietly, in hopes that people won't notice? Sure... but I'm not convinced that Disney is one of them.