With ANY centerlock setup, you should have a safety keeper. This can be a spring pin, a pair of little tines that pop out, a safety clevis, whatever keeps the nut on the hub even if it loosens up.
I was a data guy and a mechanic on a professional lemans prototype race team, I have 'knock ons' on my austin healey (early center locks, oddly without keepers). The cobra replica guys who run center nuts on their halibrands safety wire them in place for street use.
just my .02.
sjd