When skimming through hotel reviews before a trip, do you ever consider how much of what you’re reading isn’t true? One study believes it’s a worryingly high amount, and luxury hotels are the greatest perpetrators. In fact, according to the study, which looked at over 2 thousand properties, you can actually trust cheaper properties more than higher-end establishments.

The reason? Airbnb.

The findings suggest that the rise of luxury Airbnbs has prompted a huge shift in the more shadowy marketing aspects of the hotel industry. Prior to the home-sharing platform’s arrival, it was estimated that as much as 30% of all hotel reviews were fake — mainly negative reviews posted by competitors. But now, luxury hotels are choosing to post positive reviews of themselves. The findings are specific enough to show that when a high-end Airbnb appeared within one mile of a luxury hotel, a surge in positive reviews generally followed.

This is super important for you as a consumer to remember when planning your next stay. Look for specific details that can give reviews away, like oddly specific or super generic write-ups — although it wouldn’t be surprising to find out that someone was being hired to write detailed reviews about how perfect the clothes hangers were.