For those of us who use the network, There is some training issues with every agency on the network, I agree with you there. However, we users of the network know that they are not "leaving" the network, rather just switching to a different system talkgroup, however, it is universally understood by the dispatch centers that when a user "leaves" their network and goes to a neighboring towns dispatch channel, that means they are no longer the original agencies responsibility.
For example, Carmel sends Engine 41 to assist Westfield (THIS IS AN EXAMPLE). Carmel Engine 41 (hereby E41) will notify their dispatch that they are switching to westfields system. Carmel dispatcher acknowledges that. Now, from this point forward until E41 returns to Carmel dispatch channel, this truck, its manpower and equipment is the responsibility of Westfield Dispatch. Further, you will not hear the Carmel dispatch "hitting up" E41 for their 10 minute benchmarks, or about an emergency button activation (Sig52). This becomes the responsibility of Westfield Dispatchers.
Once E41 advises they are in service from Westfield's run, they will tell Westfield Dispatch that they are in service and switching back to Carmel "system". At that time, Westfield is no longer responsible for this truck.
Every radio in HamCo is programmed in with different system groups. This forces the users to switch to the respective agencies system groups. For Example all carmel fire MIGHT be labeled CFD, westfield as WFD, noblesville as NFD, etc. They have to switch "systems" in order to access the fire grounds for that particular agency, which is possibly where the "switching to so and so's system" comes into play.
It may not completely be the lack of radio training on the users of the EDACS system, rather, the lack of knowledge from operations of the network to the scanner listener.
Regards.