Dhaka, July 20 -- Although travelers are hopeful that restrictions on carrying liquids through airport security may soon be eased, many U.S. airports still haven't upgraded to advanced scanners capable of reliably detecting liquid explosives.

While it's a common frustration to dispose of drinks or limit toiletries before boarding, the real challenge lies in distinguishing between benign substances and potentially dangerous ones. The importance of this became clear after a 2006 terror plot in the UK involving liquid explosives disguised in sports drink bottles.

Homeland Security Secretary Kristi Noem recently suggested that changes to current liquid restrictions may be coming, stating, "The liquids, I'm questioning. So that may be the ne...