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.
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.