> exception that proves the rule
That's not how that works; "someone is doing this" doesn't prove a rule "no one is doing this" -- quite the opposite
"The exception that proves the rule" is for things like "closed Thursdays" (rule = open on other days), "no parking after 8 PM" (rule = parking allowed before 8 PM), "no refunds on games" (rule = refunds available on other items), etc.
But we all knew what they meant and here you are being tedious about it
You're confusing "The Exception That Proves the Rule" (in English, as used colloquially) with "exceptio probat regulam in casibus non exceptis" (in Latin, which has a use similar to what you're describing.) While the law attempts to be precise, common usage embraces ambiguity.