It depends on the game's core system. If you can transition from standing to crouch no matter what at a neutral position (0), then this block infinite is a myth. Because when the second 2~ndc makes contact on the standing opponent, they will be able to crouch or evade the second rep by letting go of block.
The block infinite has all been speculation since its discovery anyway. It hasn't been proven yet on video if 2~ndc, 2~ndc jails opponents in stand block. I've been trying to capture at least one perfect consecutive rep for a while now with no success. Which leads me to believe it probably doesn't exist. The data that Somberness shows it being a pseudo +10 and not an actual true +10 is giving me more doubts.
I'll try to record something on Sunday at GGA and see what we come up with.
Right now I'm thinking we can try:
1. Start 2~ndc on stand block, try to duck block
2. Start 2~ndc on stand block, try to duck, no block
3. Start 2~ndc on hit, and try to duck. Somberness didn't give us updated frame data on canceling normals into specials on hit, so not sure what 2~ndc on hit will be.
I have to record the Wastelands bug, anyways, so might as well do this one, too.