@tomw@abucci In Queinnec's "Lisp in Small Pieces" from 1994, this exact behaviour (except, obviously, with symbols instead of strings) is described as undesirable behaviour the Lisp community learned the hard way to get rid of ... at some point in the early 70s.
(and also how misguided it was to "reduce errors" ... by allowing people to do things they almost certainly didn't want to. Though it made for some neat tricks in early algebra systems.)