I used to see Postel's Law ("be conservative in what you send, be liberal in what you accept") quoted as some sort of antidote, but it seems to have fallen out of fashion -- I think enough people saw how that ideal played out in reality. Nowadays a JSON library feels justified throwing a fit if it sees a comment string instead of playing along with such shenanigans.
> It's not by any means exclusive to text-based protocols
Plus, I would argue text-based greatly increases the surface area for ambiguity, whereas, for instance, there are only a few ways a sane person would send an integer as bytes.
Integer encoding (as opposed to e.g. encoding of opaque binary strings) actually appears to be a bad example to me: various universal binary encoding protocols, self-describing or not, have an astounding number of unsigned and signed integer encodings among them. It’s like inventing a new one is a rite of passage or something.
Regarding binary integers, having written code for a few common binary protocols and file formats I've never had to think very hard about it (just: How long? Which endian? Signed?) but maybe it's different for older or more esoteric stuff.
It's not by any means exclusive to text-based protocols, but there's this tendency to assume everything about a text-based protocols is ‘obvious’, ‘self-documenting’ and doesn't need specifying, and to think that just because the individual elements of the protocol are human-readable, this will somehow magically make the computers using the protocol follow the Gricean maxims (if it doesn't make sense, nobody will ever say that, therefore I don't need to think about it).