I do believe that flying through a dense ash cloud is extremly hazardous and should not be attemted on purpose.
I do believe that flying through the low density ash now over Europe will cause build up inside the engines over time and will require more frequent overhauls and cause more cost to the airlines.
I do not believe that it is unjustifiably risky to fly passengers around while avoiding the high concentration area of ashes. It will only cost more money.
Proof: Test flights conducted by LH and KLM, and the F18 engines of finnish airforce, which are polluted, but did not fail while hitting the initial high density clouds last week.
If the Company calls me tomorrow, I will pack my things and go flying.
Nic