Idiom:

Rainy day ( situation of emergency )

Hit the book:
Cite
Frequent flyer
Seat allocation
Identity theft
Bin
Discard
Stub
Formulate
Facilitate

Krebs cites a reader, Cory, who contacted his website after discovering how easy it was to access someone's information from a boarding pass. Cory used an online barcode reader to read the code on a friend's boarding pass which had been posted to Facebook.