The chart on pg. 229 states that witnessing an async sleight deals 1d6-2 SV. The block for hardening says that you can never become hardened to stress from the unknown (which witnessing async sleights falls under).
Do asyncs constantly get stress from witnessing their own sleights? Do their allies also get stress every time their async buddy uses a sleight?
This is a shitpost. All craftsdwarfship is of the highest quality.