A twist bone isn't cheating. Yes, add a twist bone.
'Cheating' would be adding one or two 'Xtra' bones (if you are using Max 200
, or just parenting a point or two to the collar, and skinning to and animating those. You could manually move and rotate those bones to get whatever deformation looks good.
I consider 'cheating' adding in a bone where another solution is the more correct one (fixing the mesh). Twists aren't cheating because there is no way to produce proper deformation without them, the same way a more involved shoulder setup isn't cheating. If there is a problem of the shoulder that doesn't behave correctly (such as under the arm) cheating would be adding a bone specifically to control that deformation, which at this point, may be a viable alternative depending on deadlines.