Most would submit genetic material to 23andme and similar organizations with no restriction on its use. Yes, if could theoretically backfire not just on them, but also on their kids. But unless they see it as a near-term likelihood they will not care enough. My 2c.

(I agree with the point, but it's just not trivial to make people aware of this)

It's abundantly clear that most people don't care about how their data are used. Here "most" means people outside HN.