This comes up quite a bit in my state (Washington). You have a certification in the state but you operate under the licence of the Medical Program director in a specific district. Our county has two separate MPD's for two separate districts. They adhere to the same protocols which are county wide, but our MPD wasn't willing to allow EMT-B's that worked in a different ER and did not attend his training to work under his licence, so a new MPD was created for that area.
I also know of several career medics who work in professional departments but live in an area served by a volunteer agency. In this case the county is different and the protocols vary, so they have to get permission of the local MPD to operate under their license. Some are okay with this, others.. not so much.
The the term certification means that we have been certified to have a certain body of knowledge, but the permission (license) to use that knowledge comes from the Doctor who runs EMS in your area. Do not assume that a certification in one area will translate into another. Some MPD's require a test on the local protocols, others require that you are tested on practical skills or even to retake 'their' EMT-B class.
Since they are going to be the ones on the grill when we screw up, I think it's appropriate.
