Usually it means the dbt group is trying to get certified, so they have to prove they get results, and to prove it, their clients cant be seeing anyone else or else the results arent controlled. They dont tell you this is why - that they are basically doing it for money - or that it means they can stay in business - they just pressure the poor client! Weve seen it here on pc a few times in the past couple of years. Its kinda sucky.