This Is the Worst Thing to See On Your Boarding Pass-and No, It's Not SSSS

"The somewhat hidden clue is in the sequence number, or simply "SEQ" on a boarding pass, which references the order in which passengers can check in for a flight. That order can then be used to determine who is able to board a flight, and who is not. In fact, that same sequence number can be used to determine whether a passenger gets involuntarily bumped from a flight, according to the U.S. Department of Transportation (DOT)."

"While frequent travelers may already be familiar with the SSSS security code (which can trigger additional security screenings), another code-and the order the numbers are in-can have a big impact on boarding. The somewhat hidden clue is in the sequence number, or simply "SEQ" on a boarding pass, which references the order in which passengers can check in for a flight."

Boarding pass sequence numbers labeled SEQ indicate the order in which passengers checked in and influence boarding priority. Airlines may use check-in order, fare class, or frequent-flyer status to decide who gets a seat when flights are overbooked. Late check-in can leave passengers waiting until boarding completes and increase the risk of being involuntarily bumped. The U.S. Department of Transportation requires airlines to provide written explanations of passengers' rights and the carrier's bumping criteria to those denied seats. Travelers have reported social media accounts of being removed from flights and facing refund or rebooking difficulties.

Read at Travel + Leisure