There's no reason why the relics shouldn't be rigorously authenticated, just as scholars have subjected every hadith and chain of transmission to elaborate authentication tests. I'm not sure if there's any level of scientific inquiry applied in the bbc link you posted. All truly scientific tests conducted on turin shroud have proven it to be a hoax.
we know this isn't real because 'isa 'alaihis salam has not passed away yet. http://news.bbc.co.uk/1/hi/magazine/8615029.stm --- i was just thinking that we have many relics of the prophet sallAllahu 'alaihi wasallam too. some of them have a sanad but surely not all of them. but, is it correct to say we respect these relics because we will benefit either way? if they do have a connection with the prophet sallAllahu 'alaihi wasallam, we will get the blessings from them and if they don't, we will, inshaAllah, be rewarded for our intention in showing honour to him. i'm not sure if muslims investigate such relics as closely as these christians have. perhaps it's because we have far more of them. if we had fewer, we would probably investigate more thoroughly too.
