That's what advocate and civil rights organizations are for. I bet the likes of the EFF would be very interested in taking this case. It aligns with their incentives to take down the DMCA.
If EFF is very interested, they can find a way to test it themselves. But here, even with EFF's help the developers would be still exposed to risk. EFF is not able to say "we'll fight this for you, pay 100% of expenses and your time's worth, and go jail instead of you if things turn really bad".
