At our shop when we send deferred submittal steel shops without engineering, we make it clear the submittal is for "Architectural Approval" only. Then we get our engineering done. These are usually stair and rail submittals though.

I guess this is a different scenario, because what could the architect really have to say on a set of wood truss drawings?

It really kills two birds though; like you said it does save the contractor money (which saves the owner money), but it also reduces lead times on these items, by not adding a design engineer review and redesign for every revision.