Could you provide an example of such a thing that is prevented?

Sure. In the instance I am aware of, SQL ( and xml and few others )files are explicitly verbotten, but you can upload them as text and reference them that way; references to personal information like DOB immediately stops the inference with no clear error as to why, but referencing the same info any other way allows it go on.

It is all small things, but none of those small things are captured anywhere so whoever is on the other end has to 'discover' through trial and error.