[grey-area]

Yes they are a horrible idea for many reasons, not just security. It’s like a hidden ill-defined poorly understood dsl in strings.

You can just not use them though - you can unmarshal to a map instead and select the keys you want, perform validation etc and then set the values.

Same when publishing - I prefer to have an explicit view which defines the keys exposed rather than than publishing all by default based on these poorly understood string keys attached to types.