There are a few "unwanted" people in every profession. A few clients, who tell you "what you have to be doing", even though you know your work! And, at times, due to circumstances, you cant show them the finger.
With a Marketing agency, in particular; with unethical marketing, there is a chance that you might lose your business. Clients will know if you're marketing ethically and they would not want to work with you.
Bad clients are often difficult to deal with. They might take up too much of your time or money, or they may be unwilling to change their minds about what they want.
And, with just 1 "idiotic" client; your name may get tarnished.
The job of marketing can be very difficult. As a Marketing agency or as a job; people often have to put up with bad clients and constantly deal with the ethical dilemmas that this might bring about.
While all marketing consultants face these dilemmas, it is much more difficult for those who are not yet established or those from developing markets. They don't have the luxury of refusing a client or declining to work on a project because they feel that it is unethical. In addition, they also don't have the time to spend, talking to their clients about ethics as it takes away from their marketing efforts for other projects.
The main concern here is not whether or not you should make unethical decisions, but rather how you should go about making them if you must make them at all.
When clients ask for something that is unethical or illegal, it may be time to walk away. In the end, people will respect you more if you know when to draw a line in the sand.
If a client asks you to do work, that goes against what you believe in, it might be best to let them go and find someone else who shares their values.
The most important thing is always to do what's right for yourself and your family. In the long run, you would not want to regret your past actions.