No, I’m saying that it is up to the buyer to be aware of the risks they are taking with a purchase and that they accept them when they make that purchase. Just like any house, you get an assessment beforehand to make sure you aren’t buying a lemon. They wouldn’t pay $300k for an assessment; that is to dig their entire property. They might pay $1-2k for an archeologist to dig a soil pit and make a determination based on the findings. That is what reasonable risk avoidance looks like.

I’m also not advocating for the homeowner to liable for the entire price tag. I’m just in the camp that this was a foreseeable potential outcome.