You may already know this but we wanted to bring it to your attention in case you didn't: it's COMPLETELY LEGAL to swipe someone in with your MetroCard at the end of your ride.

According to the official MTA rules, and now more publicly, the hashtag #SwipeItForward, after 18 minutes of an unlimited Metrocard swipe, you can use your card to let someone else onto the subway or bus without breaking the law.

However, there is one condition: you cannot charge for your swipe—that's a no-no and a ticket-able offense.

Fare-beating and jumping turnstiles were one of the biggest problems last year as they unfairly target the poor, the young, the working class, the LGBTQ community, and immigrant New Yorkers of color.

Every arrest that is made ends up costing the City of New York close to $2,000 per person. In total, it can cost NYC taxpayers about $51 million dollars in 2015.

I, like many others, have been doing it before it was technically legal—I like living on the edge, paying it forward, and helping someone get where they need to go.

However, if I'm already up the stairs and you ask for a swipe, I'm not going back to the turnstile—so do us all a favor and ask for the swipe in the immediate vicinity of the turnstile but don't block riders from exiting.

Also, while we're on the topic of public transit etiquette, make sure to have your Metrocard ready before you get to the turnstile so that you're not stuck blocking people behind you as you fish through your bag for it.

Be sure to follow @SwipeItForward for more information on this #SwipeItForward campaign.

Credit: Giphy