Well...... No argument, really. I'll just point out that quite a number of devices send unsigned values in 1 or 2 byte parameters to send smaller payloads (which also improves battery life) instead of doubling the payload size.
I could name probably 5 devices I've made drivers for, or currently use, that chose to put a 0-255 value in a 1 byte payload or 0-65535 in a 2 byte.
Not saying it is right or wrong, but I am saying it isn't that uncommon. For those devices it has to be fixed in the driver - like you indicated.
