Should I develop an application for a customer that will violate the TOS of another company?

A client approached me to develop an application that I am pretty sure violates Google's TOS. It's a small application that crawls Google's search results page and extracts the results from the HTML. As far as I can tell, he is planning to use it for private purposes.

Assuming that I informed the client of the TOS problem and he denied an alternative solution (using the Google API), should I still go ahead and develop the application for him?

• Are there any possible repercussions for me, or is it "his problem" if he uses the software?


• What about ethics - Am I morally obligated to deny his request?