Actually, I think your technician is probably on the right track.
When I replaced my exhaust with a high-performance one, it took me a few months before I was able to get an intermittent check engine light from coming on. Each and every single time, the emergency brake warning light came on at the same time. At no point did I ever touch anything regarding the e-brake, but once I got the emissions system squared away, the e-brake warnings stopped too. My money is on a bug in the system somewhere that causes it to fire mistakenly. There's some others in the forums here or at acurazine that have reported the same issue with the two warnings firing at the same time.
My light was coming on because with the new exhaust system, there was much more airflow coming by the O2 sensor. It stands to reason that a bad sensor would cause the exact same problem.