A Q surcharge is applicable on tickets where the fares have been filed that will quote the ZED fare with a Q surcharge.
HKG is one example and a Q is designated as a surcharge - regardless of it's purpose.

Most carriers - not all, collect their fuel surcharge via the tax codes YQ/YR.
These are not taxes, they are surcharges, as such, they are not billable via the IATA clearing house.
I would imagine that given the current situation airlines find themselves in, will be subject to change.

What an airline chooses to do upon check in, is another matter.

I am aware that Air India has collected the fuel surcharge from colleagues via MCO before allowing them to board from India.