Based on interviews with airlines, other travel companies, and travelers, blocking customers appears to be on the rise. Understanding why airlines do it can help you avoid getting on a blacklist and ensure that your next complaint is heard.

"Customer tirades on social media can become so abusive they reach a point at which you need to block," said customer-service expert Chip Bell, author of Kaleidoscope: Delivering Innovative Service That Sparkles. "Blocking is not unlike asking an abusive, irrational customer to leave your store. It happens when you determine the emotional cost of serving the customer exceeds the return you are getting or are likely to get in the future."

Blocking stops you from being able to send a message to a company on social media. Often, but not always, it’s accompanied by the deletion of one of your offending posts. The block is sometimes temporary but usually indefinite.