Reported about 1 year ago
Travel guru Blaine N, while flying from Taiwan to Seattle in the U.S., was subjected to a high-level secondary security check due to the mysterious 'SSSS' marking on his boarding pass. This was not the first time Blaine N had encountered this situation, as security personnel informed him that once you get tagged with 'SSSS' once, the likelihood of being tagged again is quite high. The 'SSSS' marking signifies additional security checks by the TSA, targeting passengers such as those with one-way tickets, missing documents, previous prohibited item incidents, and those from high-risk countries, leading to more rigorous screening processes.
Source: YAHOO