Comment by dfranke

Yes, I'm aware, and POSIX has many such bugs that make command input or output unavoidably ambiguous if certain unexpected characters are present that they didn't think to prohibit. A lot of the revisions that went into POSIX 2024 were aimed at fixing some of these, such as standardizing find -print0 and xargs -0. The fact that this one got overlooked doesn't mean it's a good idea to make the situation worse and harder for future POSIX revisions to address.