Raid training areas

Yes. It's called launching the raid and attacking.

Enter battle, put your device on airplain mode, and practice all you want safely.

Not quite. Guilds get it on farm very quickly. It would be nice to have a place to trial teams. Airplane isn't the answer as i dont care about making a mistake in the raid but i would like a place to practice.

Ok then:

Enter battle, put your device on airplane mode, and practice all you can safely in that battle. Rinse and repeat until the raid is over.