Please don't do this. It's immoral to ride off the free work of others, then turn around and rug pull them. Either stick with open source and take the good and the bad, or go proprietary. Don't do this fake open source that harms the community. If you have a permissive license there's nothing stopping you from selling other's work and a CLA is not needed. If you have a copyleft license then a CLA defeats the entire purpose of that.
I don’t think it’s literally a search and replace but a part of the prompt that is hidden from the user and inserted either before or after the user’s prompt. Something like [all humans, unless stated otherwise, should be ethnically ambiguous]. Then when generating it’s got confused and taken it as he should be named ethnically ambiguous.