This is a delicate subject, but we always question what should the set of values and believes in translation be. There is a set that is common (or should be, IMHO) for us translators, simply because you can’t work without them.
Confidentiality. Many times, we translate privileged documents, with information about to be disclosed. What a bummer (or a nice law suit) if you were to send your friends the confidential document to show off or win some money.
Subcontracting. Do you work with other translators? Do your clients know that? If you say that you work alone and you personally handle all translation requests that that client has, then you must honor your word. In case you don’t and someone else does a horrible job, you will be penalized.
Deadlines. Your client is counting on your translation to disclose some kind of information, to print some documents or whatever. When you receive a project and agree to execute it, you must meet the deadline. There are other tasks that depend on you doing your part.
Responsibilities toward fellow translators. Once you aware that your clients charge X, you can’t charge X-Y in order to get their clients. That’s unfair competition. Ok, so you charge X-Y because you didn’t know better – well, now that you know, how about making a few changes?
Professional codes. If you are a member of a professional translation association, you must comply with their code of professional conduct. If that code says “no one can offer services into their non-native language”, you must follow it.
When we talk about ethics, we’re talking about values and believes that are subjective, and humans have this tendency of bending rules to meet their needs. So something that is good as per my principles might be bad as per yours, or vice-versa. Also, this list is not extensive. Nothing specific will answer the question “Should I overcharge this project because the client told me there’s budget on it?”, or “Should I check 100% matches when I will not be paid for it?”
When facing this kind of situation, you have to ponder. Now, if the question is to check or not to check 100% matches while translating, what have you discussed with your client? Were you requested not to check them due to budget reasons, or just because the client heard that this is the typical industry practice? Is this a lovely client, who would appreciate your feedback, or would they just reply to a comment referring to 100% matches quality that “we have no budget for that”? When you go to bed, how well will you sleep not checking these matches, or checking and not being paid for it?
Every situation has many nuances. You will have your own questions when facing this kind of situation. Or not. Anything that can be an ethics issue for me may not be for you. Will you be able to sleep well tonight, knowing you did a great job?