Eur Sam Client,
Deviation clearance, over the ocean ? if I am approaching an area of severe weather over the ocean and need to deviate before I get 'clearance' I will do so to whatever extent I need while putting out advisory calls to other aircraft
on oceanic and guard VHF frequencies, I have done so and will again as have many of us.
There is not a professional Pilot on this forum that would penetrate convective activity because they are waiting for 'permission' to avoid it.
I would do the same over land for that matter if I was unable to reach the controller in time.