You can't blame them. People they trusted told them that, so they told you.I wouldn't expect the people that are actually employed by Disney to know as much as the guests anyway.
Not everyone has seen these machines that actually can scan the inside of your body and wouldn't know how big they are. IMO, most people - especially young people! - shouldn't need to see them.
Now that I think about it, why any of us thought minimum wage Disney staff was able to read a bone scan, I don't know! I never thought of that before, though, lol. I get copies of all my reports and they're always signed by doctors, lol.