(Thanks to OTR reader Hiroko):
A pilot for Vueling, a Spanish lowfare carrier, told passengers that they should pay no attention to the empty seats on half the airplane because, "we have a safety problem" but it’s nothing to worry about. 29 rows of seats on one side of the plane were taped off causing, as you might imagine, a bit of concern from passengers. I do have to appreciate the pilot’s frankness.
Turns out one of the slides on an emergency door was broken.