Proof of Concept
$ podman build . -t flask
$ podman run -p 5000:5000 --rm flask
N=some-name NS=some-namespace
curl --silent --header "Content-Type: application/json" --data '{ "apiVersion": "admission.k8s.io/v1", "request": { "uid": "'$(openssl rand -hex 10)'", "name": "'$N'", "namespace": "'$NS'"} }' http://localhost:5000/webhook | jq .
... allowed: false
NS=foo-bar-baz (repeat curl command)
... allowed: true