One of my grandfathers was in a reserved occupation.
He applied twice to be released but was refused.
My other grandfather was given a white feather on his wedding day, despite being in the Navy!

The government did not need to encourage these things.
People desperately afraid for loved ones at the front resented any they perceived to be shirking their duty.

All this is well documented.
Some people were reluctant to serve.
Conscription was eventually required.