Don't worry - I'm not going at the hinge with a Dremel or anything like that. It's just that the adjuster on the hinge, as stock, requires the use of Loctite to keep it correctly adjusted, which is hardly the best engineering solution on a thread which isn't tightened against anything.
So what I've done is to simply find a nyloc nut of the right size, unthreaded the adjuster, added the nut, adjusted the hinge to the correct clamp closing torque then, nip the nut up tight against the 'non-adjustable' part of the clamp lever. Et voila - no scary thoughts of the hinge clamp working loose on longer rides, or over rough paths.
Was worried that it might foul the hinge mechanism when fully open or fully closed but there's no issues.
Big question is Dahon, why don't you fit a locknut as standard. I know the bike business works on slim margins, but come on...
NB: Just from a legal angle. I'm not recommending this mod as safe, guaranteed, whatever. I'm just saying that I've done it and I think it'll make the bike safer... So don't sue me!