The following are disadvantage which the professional may face if auditing standard would be enforced by law/statutes.
To be enforceable by statues the standard would have to be applied to all circumstances and thus need to be very general and broad in their instruction. this might reduce their usefulness to the auditors.
Auditors might spend unnecessary time ensuring that they are complied with the laws rather than considering the quality of the services to their client.
Finally it should be considered whether fully statutory backing for standard would force auditors into narrow view and approaches which might gradually impair the quality of accounting and auditing practices.