The Killers' songs are not as demanding vocally as perhaps a U2 song and Flowers is no vocal acrobat so I am sure he can sing through a bad throat.
Shows have also been cancelled in Europe.
Maybe there is a deeper reason behind the cancellation? Perhaps one or a few of them have their own personal matters to deal with?
Also, what did you guys think of the Here With Me video?
I found it quite odd for a song that accessible and poppy to have a video that odd and scary, but that's what you get with Tim Burton.