http://www.idpf.org/2007/ops/OPS_2.0...tml#Section3.1
"Reading Systems must support all CSS2 selectors."
It is true that the specification doesn't specify what "support" means - maybe that term really
does include "crashing your device" :-)
Not that it matters. Fact is, LRF will not be supported by Kovid anymore. It doesn't matter whether there are or are not reasons for people to stick to LRF.