How do I stop staff pasting sensitive data into public AI tools without banning AI outright?

Bans don't stop the pasting — they move it onto phones and personal accounts. Substitute instead: give staff a governed workspace with models as capable as the ones they're sneaking off to use, signed in with the work identity they already have, with usage visible on a dashboard — when the safe path is also the best path, the paste problem mostly solves itself.