You do not understand what transaction malleability is.  If I am taking an in person transaction sent to my own Bitcoin address and I see it unconfirmed, and it is for some reason altered, I still get the Bitcoins.  They just have a different transaction ID but they end up in my wallet anyhow.  

PS - I took an in person Bitcoin transaction today, along with doing several purchases with Bitcoin and selling online items out of my store.