You must have shared a Netflix account with friends or must have used someone else account. People take a sharing-subscription whereas Netflix account and password sharing is very normal. But this thing is not liked by Netflix and the company is planning to ban account sharing.
Then users will not be able to share their Netflix password in the future. Netflix’s subscription cost is high. Due to the introduction of this feature, many subscribers might leave it. Netflix is testing a new feature. With this feature, people logged into a shared account are being given a warning.