"Don't believe everything you see on Instagram" seems to be the lesson of 2019. First, influencers were caught posing next to a serene blue lake that was actually a toxic waste dump. Now, one woman totally broke the sister code to call out her sibling for pretending to go hiking.OK, I just have to say, I feel like every Instagram post where someone is hiking is fake. Unless your face is beet red and sweat is dripping from your nose and your legs are cut up and you look miserable, there's no way you are actually hiking. And no one on Instagram takes hiking pictures of themselves looking like that.Second of all, if you're going to fake hiking pictures, you better be prepared to get caught. That's exactly what happened to Casey Sosnowski.Carly Sosnowski took to Twitter recently to totally bust her sister for taking Instagram photos in their backyard that made it look like she was going on a hike. In the photo on the left, it's clear that her sister Casey is in their backyard in workout clothes posing for pictures.The picture on the right is Casey's actual Instagram post that came out of that backyard photo sesh. In the post, she's wearing sneakers and holding a water bottle, and she shamelessly captioned it, "Nature is the ultimate healer to all our problems #naturelovers."She even used the location tag to place herself at a trail! Sneaky sneaky...or so she thought in the moment, at least. What was she thinking?! Well, she told Insider, "I told my sister let's go outside and take pictures by our wooded area because I haven't posted on Instagram since the beginning of July, so I figured it was about time I posted something."Apparently, she didn't care if that something was a lie. "I thought the background was really pretty," Casey continued, "so we took pictures over there, and after I got home and posted it I told my family, 'Look, it looks like I was going for a hike.' So then my sister Carly posted it."It's clear she knew exactly what she was doing, and honestly, good for her. No one looks good when they're actually hiking. The only way to take flattering hiking photos is to fake them. Casey thought it was funny when her sister Carly called her out on Twitter. "I'm a pretty chill person overall so it didn't bother me, and then it blew up and I was like 'whoa.'"And blow up, it did. Carly's tweet gained over 41,000 retweets and 277,000 likes. Casey was officially outed, so there was nothing left to do but...respond to her sister's tweet.In response, Carly wrote, cheekily, "How was your hike?" The bickering was all in good fun, though, and at least Casey got more traffic to her Instagram than she would have if her sister didn't call her out!Since the story went viral, Casey reposted her pictures to Instagram, this time with a new, more honest caption.There's nothing like the brutal ruthlessness of sisterly love, am I right? As if this was her plan the entire time, Casey told Insider, "It just goes to show that not everyone's life is as perfect as it seems on Instagram." Way to land on your feet, Casey! Your feet, which are covered in perfectly clean, stylish sneakers that definitely haven't spent any time on the trail.