Hello! Welcome to Beyond Soy!
Sometimes people assume that we can figure out if a food contains soy just by looking at it. For example, not labeling the food at a buffet because it should be "easy to figure out what it is", but this isn't true and makes it challenging to eat. Figuring out what a food is at a buffet isn't hard (although we've all seen dishes where we questioned what was being served, that is definitely the exception and not the rule), but figuring out what a food contains is a very different matter.
This issue isn't exclusively related to a soy intolerance, allergy, or sensitivity. As with all allergens, the easy food to avoid is the one where you can see the allergen, such as when it is a major component of the food (a great example for soy is avoiding tofu). The more challenging foods to avoid are foods with invisible allergens. We can't tell just by looking if the salad dressing on the buffet contains soybean oil, or if the rolls in the basket contain soy flour. So, as a result, we need to avoid these foods if they aren't labeled.
When other people assume that it is easy to see the allergens in a food, it causes us to skip over more foods than probably necessary. Out of caution, we need to assume that every food contains soy unless otherwise labeled. Yes, we do make educated guesses to determine what we can eat, but these guesses can still be risky in some situations.
A better practice when providing food is to make no assumptions. Present all allergen information up front, or at the very least provide a point of contact to ask for the ingredient information. Allergens aren't visible in all situations, and providing some information can open up a larger assortment of food to a greater number of people. When it comes to food intolerances, allergies, or sensitivities, more information is always better!