IIRC, a Jon Armstrong idea is that the stealing hand is not palm down, but more in a reversed "C" formation, with back of the hand towards the spec. Then the card can be pulled out and replaced parallel with the deck with no noise. You have to be careful of angles, but at all but the closest distances it's actually covered except on your far left. A slight angling to the left covers it. The angles at a table are similar to what a gambler's cop in right hand at table would be.