I too stick my phone there to avoid dropping it in a public toilet.
I also have a small zippered coin purse that I will stick cash and credit cards in when I am anywhere that I worry about pickpockets/purse snatchers. That way I know that even if I am robbed I will still have my actual important valuables safe. I definitely cannot pull it out in a dignified way, but will try to walk somewhere secluded and/or turn my back before removing the wallet and before returning it. I really don't sweat that much from my boobs, so even in summer I have trouble seeing it as "SOOOO GROSS OMG!!!" I do have a wallet between the cards/cash and my skin, though, so maybe that makes a difference. Or I am just trashy.
