The Job is Not Over Until the Paper Work is Done!
In most regulatory jurisdictions the post-flight entry and signature is required by law (the national law not just your Ops Manual). Non-compliance in many places is punishable on conviction by a fine or imprisonment, or the matter may even be dealt with by ‘administrative means’, which allows them to pull your license / certificate if you have been frequently upsetting the regulator or they really don’t like you.
Even where a ‘Just Culture’ is in place such deviant behaviour would perhaps justify some form of retribution.