Sadly, I don't think we're up to the challenge. Not because we're unable to agree a set of guidelines, but because we've no power to enforce them.

All the examples Brad has given are ones where there is a degree of enforcement. In most of those cases, it's enshrined in law - a doctor who's struck off is no longer legally allowed to either practice medicine or call themselves a doctor, so (s)he has no choice but to abide by the rules. On the other hand, anyone can call themselves an estate agent, but if they fail to abide by their industry guidelines they'll lose their customers, so the guidelines still have teeth.

As for DBAs, I see very few examples of wilful negligence. I see plenty of examples of DBAs being forced into ethically compromised situations by their employers in the name of expedience, but, being cynical, I suspect a DBA who's prepared to put company before ethics is likely to be more, not less, employable. I also see plenty of examples of DBAs who've overstated their true abilities to get the job, but that's not an issue of guidelines, it's an issue within the recruitment process, since there are plenty of inept accountants and engineers too.

So, unless governments are inclined to put a legal definition and associated obligations to the term Database Administrator, we're severely limited in the clout we can associate with any set of guidelines. The only workable solution I can see is, as Brad suggested, that all the major database manufacturers include a clause in their certifications which allows the certification to be withdrawn if a specified code of conduct isn't followed. Employers like certifications, so that's the only way misbehaving DBAs could be forcibly made less employable, although it would remain to be seen how companies would view any new qualifications that might run counter to their wishes.

Apologies for waffling on, but in short I believe the bulk of our effort should be in lobbying the RDBMS manufacturers to incorporate an ethical code in their certs rather than fine-tuning the ethical code itself.