I have fished several waters where you have to use a landing net on every fish caught,bloody ridiculous,netting a minnow sized fry...
I have sen that rule , but some places say use discretion.
As for unhooking in net across the knee , I have found it to be a safer and quicker option than using a mat,
And I will never use dip tanks for nets, some have scum on them ,rubbish such as tins floating in them .
In a match we peg them out behind us when we are setting up , then put them in the water about 15 minutes before the all in.