Sometimes it is comparatively easy to effectively ban a certain kind of fraud attempt, whereas actual success of the attempt would be impossible to prosecute because the victims can only be victims when they not even notice any wrongdoing. Not banning the attempt.

In that case, you have a choice between banning attempts, together with everything that is indistinguishable from an attempt, versus effectively giving fraudsters free reign, despite having a law that technically forbids successful execution of an attempt. Classic legal balancing act: how valuable is the freedom of dressing up as a postman compared to not having to question the authenticity of each and every on of them?

Well now there is one where a judge and/or jury don't have to determine if wearing a letter carrier uniform is fraud or freedom of expression.