Indeed, if the result is to be encoded with UTF-8, using 1-byte separators vs the multi-byte encoding of (241F) would make sense to me.

I'd also prefer if escapes were done in the "traditional" manner of, for example, "\t" for a tab because you can then read in stuff with something like input.split("\t").map(unescape); you know any actual tab character in the input is a field separator, and then you can go through the fields to put back the escaped ones.