I am pretty lenient when it comes to participation in the Harappa Ancestry Project. I accept almost all comers, even those with no connection to South Asia and neighboring regions.
While I ask about ethnic background, I don't release it publicly unless I have consent from the participant.
I do expect a few things from project participants. One is that they will be honest about the information they share with me.
I see no need for anyone to lie about their ethnicity. It's better just to withhold that information if you are so concerned.
There is also no reason not to tell me if you have a close relative participating since I do accept data from relatives (with the proviso that only unrelated samples can be included in most analyses). It's possible that you might not know that a 1st or 2nd degree relative is already in the project. That's not a problem; knowing a relative is in the project and not telling me is.
Also if you send me genomes that are 95% identical (IBS2: 849,145 SNPs) under different names, I will know. And I will remove you from the project.