I fall into this catagory. I was born in Hexham and we lived in Prudhoe for the first 3 years of my life before my family left the area for my Dads work. Mum is a born and raised Geordie and we were back multiple times a year to see extended family who live in Newcastle proper.
While I don't consider myself a true Geordie as I didnt grow up in the area, the sense of belonging and 'home' I get whenever i'm back in the area gives me a great deal of happiness. I don't think i'd be allowed to support any other club.