This flag would be used with actors that are intent upon weaving, yet have no collision checks such as if it was a +NOINTERACTION object. In fact, I would think it's safe to say that only if NOINTERACTION was specified, then this flag would be taken into account as well.
Currently, things with A_Weave and +NOINTERACTION will ultimately still "hit" the ceilings/floors/walls on it's Y and Z axis (side/top/bottom respectively) and it would indirectly continue hitting them as well. This is most noticeable on actors which call A_Weave in a consistent manner.
I'd also consider this a "limited use" flag as it would only be for A_Weave to check.