If you show up to a "black tie" event in a t-shirt and jeans you are breaking a ; if you show up to a "black tie" event and you learn human flesh is being served for dinner your host is breaking a .

- Folkway; taboo.

Explanation:

'Folkway' is elucidated as the conventional behavior or style of a specific cultural group or community while taboo is described as the implicit prohibition or restriction owing to a social or cultural custom.

In the given example, if a person wears a 'black tie' along with jeans and t-shirt it would demonstrate breaking of 'folkway' as it reflects the escape from the traditional custom or style of dressing but if one shows up to a 'black tie' and infers that 'human flesh would be served in dinner' it breaks the 'taboo' as he failed to consider the social restriction.