AWOL:
COBOL compiler was smart enough to know what the situation was
That's because COBOL has the MOVE verb (looking back on my COBOL career, I felt like I was SHOUTING all the time, but then 132 column line-printers and teletypes didn't do lower-case) for assignment, and reserved '=' for comparison.
Algol and Pascal have ':=' for assignment.
I can only assume K&R were seriously into brevity.
We had a print chain that had lower case. Seldom used it, but it did exist.