What is needed is data and those who govern the airspace to justify their decisions based on that data. Surely that is logical ?
I find it a bit funny to outfit testplanes with probes to fly into the cloud (as is being done at slowmo speed in Germany) to measure a particle concentration to then calculate or deduct a risk percentage for engines to fail/pitots to clog while aircraft have already flown through it and have been assessed. It is like proving the obvious.
Nic