WMATA hardly ever grants permission to film in any of their facilities. I recall seeing an outdoor Metro platform in one movie, one guy was chasing another guy in and out of a stopped train. Wish I could remember what it was, I want to say the French Connection sequel with Ed O’Neill but IMDb only has NYC & Tokyo as locations for it.
The worst example I’ve heard of involved an obvious NYC subway train standing in for Metro with passengers disembarking into the Old Post Office Pavilion, instead of using Federal Triangle’s escalators across the street.