Between his physical senses and her magical ones it would have to be a damn sneaky bastard to catch them unawares. And if that were the case, they would probably be dead before they knew it was there.
Her brain was suddenly stuck on whhoooaaaa after he said that. She looked at him in astonishment first. "...really?" Then the look became something both girlish and womanly, somewhere between crush and lusty and her brain was chasing its own tail yipping happily. "Thanks."