In the pay-TV era where streaming services are quickly outpacing cable and satellite companies in nearly all metrics that matter to investors and Wall Street, there is one advantage that no streaming services will readily admit is a strength, but could be a major problem that limits growth in the years to come: password sharing.

The concept is pretty simple. Open a Netflix or other streaming service account, and you can share your username and password with friends and family members. Years ago, lots of people potentially gaining access to content with one would have required multiple subscriptions to cable or satellite. That could save a lot of money for an entire family or a group of friends.

Of course, this so-called advantage—and surely the streaming services don’t see it as one—is a double-edged sword. On the one hand, sharing passwords, at least for now, likely does not limit the growth of streaming services, as the market should be poised for expansion during at least the next few years. After all, more and more people are “cutting the cord” and moving away from traditional cable and satellite services or are adding streaming services separately. Password sharing, and its obvious advantages for the consumer, are likely a growth driver.

But what happens when growth stops? What happens when subscriber numbers aren’t moving up at the rates they are now and Wall Street demands higher profits? What happens when investors streaming services as a mature platform that now needs to deliver long term value for their shareholders?

Clearly, the streaming services have options to block password sharing in ways that are fairly easy to implement. Many services offer several usernames as part of one account and they can block multiple people trying to use the same username simultaneously by looking at the IP addresses of those trying to connect.

But will there be a backlash? Will people start canceling their subscriptions if password sharing is suddenly stopped by say Netflix or other streaming services?

The trick, I would argue, is to start educating people now that password sharing is, in fact, piracy. Not paying for a product or service, no matter how innocent, is wrong. Streaming services surely don’t want to see revenue and profits slip at a later date once the days of easy growth come to an end. No one wants to let the situation get out of hand like when file-trading services damaged the record and film industries years ago. No one wants to get Napstered.

The good news is the streaming industry is starting to think about this problem and how to combat it while trying to ensure public opinion does not turn against them. My advice would be to start with a simple warning system. If someone is clearly sharing usernames and passwords with a predetermined amount of people over a certain amount of time, a friendly warning should be in order. If that does not work, less friendly warnings could be next. Canceling a subscriber’s membership or legal action would only be reserved for the most extreme cases.

Netflix and other streaming companies can tackle this in a way that does not need to be a PR nightmare. I would say tread carefully, don’t overstate the issues—but don’t also let it get out of hand either.

Harry J. Kazianis serves as a senior director at the Center for the National Interest and Executive Editor of their publishing arm, the National Interest. You can follow him (or yell at him) on Twitter: @Grecianformula.