Any SEO can and should be held to a code of conduct, an ethical code if you will. I adhere to the SEO code of conduct written by Jennifer Sullivan Cassidy.
Here's an excerpt: "In the area of General Ethics, the SEO shall not:
* Engage in any behaviors that will intentionally harm a client or a competitor. This includes performing black-hat techniques that may get that client's site banned from the search engines, or purposefully interfering with a competitor's site as to try and get their site dropped from the search engine in order to get their client's website into a better position.
* Intentionally engage in activities in direct violation of a search engine's guidelines. Again, these types of behaviors can impose penalties by search engines, or banning from the search engine indexes altogether.
* Purposefully engage in behavior that breaches a client's confidentiality or privacy. An SEO many times has access to your sensitive materials on your website, including documents, logins, passwords, product information and other items. It is not acceptable for an SEO to make this information public, nor is it acceptable for the SEO to discuss your account with other SEOs that are not particularly working on your account. It is in your best interest to include a clause in your contract with the SEO that specifically protects your confidentiality and privacy.
* Deliberately violate any laws, including but not limited to trademark or copyright laws. SEOs that use copyrighted names, like Google or PayPal or Sony or even misspellings of trademarked names, in order to inflate a site's ranking is considered illegal, and punishable by law. It won't be the SEO in trouble, but rather you and your site will take the fall. Make sure there is a clause in your contract that addresses this issue.
* Falsely claim another's work to be their own. SEOs sometimes do this in order to make their portfolio look impressive, especially when they know a client probably can't or won't follow up on their portfolio examples. It is a good idea to ask the SEO for specific references, and outline the exact work that was done for the client, and ask for permission to contact that client to corroborate the SEO's claims.
* Intentionally mislead, harm, or offend a consumer. This includes bait and switch tactics intent on bringing traffic to the site, or making a visitor believe the site is something it is not. An example of this is to use terms like "Disney" or "Teddy Bear" in order to get a visitor to come to their website, when in actuality it is an illegal warez site or a porn site.
* Disparage other SEO consultants, SEO companies, or former and current clients in public, even if you know they have engaged in unethical techniques, or treated the SEO badly. It is never professional for an SEO to bad-mouth another SEO or SEO company to you or anyone else. It's just bad business practices, and should make you wonder if the SEO will talk about you in the same way.
* Fail to stay current on search engine updates, changes, news, training or education. It is in your best interest that your SEO know what's going on today in the search engine world, due to the fluid nature of search engine changes which occur very frequently."
Head over to SEOChat for the rest of the SEO code of conduct written by Cassidy. Note: I also adhere to the remainder of the code of conduct. The reason I haven't copy-pasted the rest of it here is that I feel the quality of the writing/code deserves for traffic to be sent to read it in its original location.