My airline issues us with cabin shoes which are put on when we board the a/c and removed after the pax have disembarked. I think this is standard with the majority of long haul carriers, although maybe more for comfort than safety purposes.
I think that this safety issue is overlooked by the majority of short haul carriers (who don't issue flats as standard). I certainly wouldn't want to be evacuating an a/c in a pair of 3 inch heels, let alone my bare feet!