I'm not sure we'd have to. 'Always material' infringements are very much the exception rather than the rule (I can only think of knock-on, throw forward and foul play) and that makes sense and doesn't even need stating in the law book - though maybe I'm hard-wired to think that. I don't think it'd make sense for playing the ball on the ground to be considered in the same category.
He'll correct me if I am wrong, but my impression is that Ian is in the 'always material' camp for this one.
TBH though, I think we'll be waiting a long time for the lawmakers to change anything - I can't see this being an issue that's come to their attention.
I dunno, it seems a question that is often asked, SA Refs seem to have dealt with it twice, I wouldn't be surprised to see it come up as an official clarifcation at some point.