Vagueness Data

I’ve long been interested in the interaction of negation with vague terms, but sme of the ‘data’ I used might have been idiosyncratic usage. But I just noticed the following line from The Magnetic Fields’ song “I Don’t Believe You”.

bq. You tell me I’m not not cute.

A theory of vagueness should have a story about why this communicates something very different from “You’re cute”.