Suggestion as alternate for the AABB boundary box, how about switching over to volume based solution. (calculate a volume and set the boundary here, a organic body has always a way smaller volume then a house or big boulder)
This way you could not have such a static mainly annoying boundary but one that allows more freedom while still preventing people from wearing for example a house just to annoy someone.
This way people could do also animations as they like.
The calculation could be done in a similar way like Sansar already calculates the colission mesh, create a convex hull and then use this simpliefied shape for the calculation.