My Shimano cassette lockrings have a torque value of 40 N*m stamped on them. That's pretty damn tight, and I can't figure out why it would need to be that tight -- the lockring doesn't carry any drive torque, and it's got serrations to prevent it from backing off.
With such a tight lockring you'd need to carry a chainwhip and a wrench big enough to undo the ring in case you need to replace a right side spoke in the field. That's a lot of extra stuff to be taking on tour.
What can go wrong with a looser lockring?