If there is no problem than it won't be too difficult to persuade the manufacturers to loosen their guidelines then, will it?
lol, that's a good one! The old 'lightning response' of the aviation regulatory authorities and manufacturers!!!
I don't think this is about safety anymore, this is about ass covering. The manufacturers and authorities aren't losing money, so why should they rush to stick their necks on the line when there's a tinest chance they might get a lawsuit thrown at them?! Why not wait for a year or so, see if anyone does find any damage? I still believe that birds hold a far greater risk to commercial aviation than dispersed volcanic ash.