There are lots of new people who register with just a single name, "Veni" or "ravi" for example.
The moderators and other users often politely point these people to the naming policy.
Can't the forum software be changed, so that it checks at least if someone enters a first name and last name separated by a space, instead of just a single name? That would save us a lot of work reminding people of the policy.
The current software does that already (well actually it has separate "first name" and "last name" fields, both of which must be present to create an account). So at the time an account is created the account will have both a first and a last name.
However many JavaRanch members then go and modify their profile, and the modification screen just has the one "display name" field.