50,000 people work at Walt Disney World. They go through a lot of training, but at the same time no one single cast member is going to know "EVERYTHING" - and a lot of the knowledge that a cast member gains comes with experiance.
I remember my first two weeks, I would often times have to look at a map to help guide guests to locations that I had only caught a "glimpse" of during my property training. However, I played it off as opening the map to physically show them - in all reality, it was for myself too. Even after I had been in my location for a while, there were even basic questions I could not answer about the other parks - even thought I had been in them.
Thus even if a Cast Member doesn't have an "Earning my Ears" sticker on their name tag, that doesn't mean that they are going to know everything, and sometimes cast members will confuese what you are seeking for something completely different. You come up asking where such and such water fountain is, they may picture a completely different one. On top of that, most guests have other names for attractions and locations ( Planet Place, Treasure Island, Pleasure Palace, Disney World Store, the big store, La Cirque, East Side are just a few I have heard of at Downtown Disney. Test Place, Test Run, Crash Track are some I've heard for Test Track alone.
It's always the Cast Member's best intention when answering your question.
97,000+ members on DIS and around 50,000 cast members. DIS definately has a larger "pool" to pull from.