Why would you convert an identifier to ascii as if it were hex? And it seems unlikely that (eg) paypal would do so? But, sure, it's just one idea. You can add

Why would you convert an identifier to ascii as if it were hex? And it seems unlikely that (eg) paypal would do so? But, sure, it's just one idea. You can add more layers to make it even less likely something will seem problematic to someone somewhere; a 100% guarantee seems impossible, especially if you are going to allow things like above "What if we brainstorm for a way this could be a puzzle where the answer is a problematic word to someone". No "scanner" will even possibly catch every possible thing in that domain, no matter how unlikely.