Well, the Gods aren't omnipotent or omniscient, and Athar don't radiate some sort of visible aura of atheism, either.
If she started walking into churches and kicking over the pews and taking a dump on the altar? Sure, she'd probably get chased down by the local Paladins and Clerics. If she did some REAL damage she might even get hunted by a proxy or avatar.
But as long as she isn't doing anything major, she's not at risk.
It could be a cliché that whenever they went somewhere new, there'd be a pack of the local Clerics and Paladins accusing her of some sort of childish prank on their church, like buckets of water above the doors, etc.