Who executes certification vs. forum-shopping?

Who executes certification against forum-shopping? It is the plaintiff or principal party who executes the certification under oath (Rule 7, Sec. 5). It must be signed by the party himself and cannot be signed by his counsels. The reason the certification against forum shopping is required to be accomplished by petitioner himself is because only the petitioner himself has actual knowledge of whether or not he has initiated similar actions or proceedings in different courts or agencies. (Digital Microwave Corp. vs. CA, March 16, 2000)