Within the framework of a request to show authorization an alleged infringer is asked for which reasons he believes to be entitled to use the protected subject-matter. This step is advisable particularly with respect to protective rights which have been registered without a substantive examination (utility model, trademark, design), since eventually the other party can actually prove a prior right to use, so that your protective right may possibly not be legally valid. Thus, the purpose of an authorization inquiry is to ascertain whether an infringement of a protective right exists at all.
However, if it has already been ascertained that there is an infringement of a protective right and the third party has no prior rights, an authorization inquiry is not necessary.