I don't think a chief should recall the ALS, even if he is an EMT. I think that should be up to the BLS providers that are going to be responsible for pt. care, even if it is a pt. refusal. Unfortunately, I've had this happen to me. As a BLS provider, I've rolled into a scene when the ALS has been canceled, only to find a pt. that would have benefited from ALS intervention. I need to ask for ALS to be redispatched, and then have received a lecture from the ALS provider for being canceled in the first place, when it wasn't my fault. I've had QRS units do this, also. Ultimately, unless that person is going to take responsibility for the pt., no one should be canceling ALS.
I guess I need to clarify my question better. On scene there is a walking wounded self extricated from a vehicle. Vehicle has rolled once with airbag deployment and some intrusion into passenger compartment. Obvious AOB. Prior to BLS arriving on scene, chief recalls medic. Upon secondary survey you find pt. nuero. functions are diminishing on one side. You redispatch the medics to meet you enroute. Did that chief have the right to recall the medics to begin with?