What if counsel signs a pleading?

A certification signed by a counsel is a defective certification and is a valid cause for dismissal (Far Eastern Shipping Company vs. CA). This is the general and prevailing rule. A certification by counsel and not by the principal party himself is no certification at all.
The reason for requiring that it must be signed by the principal party himself is that he has actual knowledge, or knows better than anyone else, whether he has initiated similar action/s in other courts, agencies or tribunals. Their lawyer‘s explanation that they were out of town at the time their petition was filed with the CA is bereft of basis. That explanation is an afterthought as it was not alleged by counsel in her certification against forum shopping (Go vs. Rico) ADVERTISEMENT: Work from home! Be an online English tutor. Earn at least PHP100/hour..