x != 'a' & 'b' and x = 'a' | 'b' Mean the same thing

[mtoy-googly-moogly]

There is code in our ecommerce example which uses

status != 'Cancelled' & 'Returned'

.. which works, but we had problems with users trying to use != and &, so we started warning on that instead of thinking through the problems
... and then without thinking it through, we did IN so now

status != 'Cancelled' | 'Returned'

writes status NOT IN ('Cancelled','Returned') is NOT the same as the alternation tree applied to the value.

The time has come to have more than a "put a bandaid on it and go implement something new" solution to this.