The only real solution here seems to be to find a way to hold HackerRank to account for this (in the most costly way possible), so they face an incentive to do meaningful due diligence and evaluate before partnering with someone that acts as their agent.
Ultimately it wasn't them that did this, but unless they bear a significant cost from doing so, which causes them to pursue their DMCA agent for negligence or breach of contract (or whatever other remedy is available to them), I don't see this type of thing changing.
Once a DMCA agent becomes a liability, the market will be forced to mature, and buyers will need to do due diligence to minimise their likelihood of being opened up to a large and costly battle as a result of the negligence of their agent.
The only real solution here seems to be to find a way to hold HackerRank to account for this (in the most costly way possible), so they face an incentive to do meaningful due diligence and evaluate before partnering with someone that acts as their agent.
Ultimately it wasn't them that did this, but unless they bear a significant cost from doing so, which causes them to pursue their DMCA agent for negligence or breach of contract (or whatever other remedy is available to them), I don't see this type of thing changing.
Once a DMCA agent becomes a liability, the market will be forced to mature, and buyers will need to do due diligence to minimise their likelihood of being opened up to a large and costly battle as a result of the negligence of their agent.