Associated community ticket: https://github.community/t/did-dockerhub-rate-limit-affect-github-action/128158

The customer noticed that Docker hub has updated their pricing, Download rate limit and retention policy recently. He is wondering if the download rate limit affects on Github Action.
Will the steps like below are affected?

jobs:
  my_first_job:
    steps:
      - uses: docker://alpine:3.11

jobs:
  my_first_job:
    steps:
      - run: docker pull alpine:3.11

According to the introductions from the docs about "Download rate limit", the limit seems only applies for the anonymous users with an eventual limit of 100 pulls per six hours. Logged in users will not be affected at this time.

I setup a workflow with the following step that pull an image 101 times in a loop.

- name: Test Docker download rate limits
  run: |
    docker image ls
    index=1
    while [ $index -le 101 ]
    do
      echo "---------------------------------------------------------------------------------------"
      echo "Pull image $index times"
      docker pull alpine:3.11
      docker image ls
      index=$(( $index + 1 ))
      docker image rm alpine:3.11
    done
    docker image ls

It can successfully download the image 101 times without any warning or error messages about the download rate limit.
Note: Consider there may be image cache, I have used the "docker image rm" command to remove the image every time before downloading it again.

Question:
When we try to pull some public images in the workflow, if we do not login with any of our accounts, whether GitHub has a default account to login the docker?
If not, in my above example, why it is not hit the download rate limit?