Maybe. But you also know your taste. If you know you like a lot of pepper in something, and if you don’t believe in the concept of too much pepper, it’s a safe bet you can just add pepper to anything put in front of you and it will be fine. Also some people just operate on muscle memory, throwing a dash of salt on something is just part of the eating ritual. That’s the funny part about the whole “question” Edison fails somebody for making assumptions, but in the process makes an assumption.
That doesn’t hold up in any way.
You don’t know what is in that bowl, Edison wasn’t making a presumption at all, he was watching to see if the person did, or even worst, did it out of habit because he never checks.