Some users have spotted a screen urging them to set up their own account to keep watching if they "don't live with the other of this account".
A spokesperson for the streaming platform told the BBC:
"This test is designed to help ensure that people using Netflix accounts are authorized to do so."
It's currently unknown whether or not the company will give the trial a full rollout across its whole network. Those who see the message can verify they are allowed access to the account in question by using a code, which will be sent via email or text.
Although many streaming services - including the likes of Netflix, Amazon Prime and Disney+ - let users create multiple profile within one account, the terms and conditions rule that these are meant to be set up for people in the same household.
Back in 2016, the company's co-founder and chief executive Reed Hastings noted:
"Password sharing is something you have to learn to live with, because there's so much legitimate password sharing, like you sharing with your spouse, with your kids, so there's no bright line, and we're doing fine as is."
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