In 2012 I made the mistake of ordering from growers who had rust. I learned the hard way what my original daylily mentor had told me at the get go. If they don't have really cold winters they probably have rust. Anyway, I wouldn't put up with the big time rusters and pitched them immediately. The list below are of those daylilies that showed nary a spot of rust even when ones around them had it. Since most of my daylilies are in pots I removed the rusters from amongst them later on of course, but they'd still had time to become infected yet managed to remain clean:
Bahama Butterscotch
Citrix
Cluster Muster
Coral Corduroy
Dutch Yellow Truffle
Linda Beck
Sour Puss
Witches Wink
Yesterday Memories
As a variety previously mentioned, Mr. Lucky had one of the lighter cases of rust which spared it from immediate disposal. However it died over winter, so whether it would have been clean the next year after our cold winter is unknowable. Since that one year I've not had rust again and am careful about who I order from and their weather conditions over winter.
Maryl