in reply to Re^6: Global substitution of non-base-plane Unicode characters
in thread Global substitution of non-base-plane Unicode characters

This really has nothing to do with what, if anything, I find "troublesome".

You hit the nail on the head with your earlier post: "Using printf in this admittedly unusual way ...".

Writing code in an unusual way (without any indication of why this was done) makes future maintenance error-prone.

Yes, there's more than one way to do it. Here's another, that simply adds a comment, that I would consider better:

printf "\x{FEFF}"; # printf() so $\ is not appended

-- Ken