sys_guid() not pseudo-random

It turns out that on some platforms sys_guid() is NOT pseudo-random, see also http://feuerthoughts.blogspot.ch/2006/02/watch-out-for-sequential-oracle-guids.html
RFC 4122  only specifies version 4 to be pseudo-random (see also Wikipedia). Oracle however specifies it non to be pseudo-random (see also its example).