Absence of GZK Cutoff and Test of de Sitter Invariant Special Relativity

The possibility that the absence of Greisen--Zatsepin--Kuz’min (GZK) cutoff is used to discriminate between de Sitter invariant special relativity (SR_c,R) and general relativity (GR) is studied.
A careful investigation shows, unfortunately, that the phenomenon fails to distinguish SR_c,R from GR, at least, at classical level.