Wasn't there a whole big thing about how attacks that have no travel time or indication of activation are overpowered? Sure, there's the dispersing streams, but that's not really an indication of an attack, just an indication of a release of power. 

If, on the other hand, the streams were instead launched toward Arthur, where they burrowed into the stone then re-appeared as the chains, I'd imagine the whole thing would be a lot less questionable. Apart from having an unspecified holding strength. That should still be clarified and approved by LeeRoy.

Edit: Then again, if the chains are similar to steel like the armor is then the holding strength can be extrapolated from that I suppose, but that isn't confirmed either.