Exactly. At one of my previous companies, every time a client was allowed to bypass my project manager, it ended up doubling my workload and cutting in significantly to my development time.

Even worse, some clients would try to get me to agree to things (e.g. "minor tweaks" at no additional cost) that really weren't up to me to decide, sometimes after the project manager already told them no. It always put me in an awkward position, making it even harder to get my actual work done.