The Transportation Security Administration rule requiring all passengers - even those with no luggage or carry-on bags - to obtain a boarding pass before clearing security-screening checkpoints will now apply to Sea-Tac Airport.

At the checkpoint, travelers will be asked to present a boarding pass and photo identification. Rather than checking some passengers at every gate, agents will search travelers at randomly selected gates. This is designed to "reduce the hassle-factor" for travelers, said Michael Jackson, deputy transportation secretary.

The rule also is phasing in at Milwaukee's Gen. Mitchell International Airport, Cincinnati/Northern Kentucky International Airport, Houston's Bush Intercontinental Airport, Boston's Logan International Airport, Memphis International Airport, Charlotte/Douglas International Airport in North Carolina and Pittsburgh International Airport. It will be implemented nationwide next year.