I have to admit I've said it occasionally in the past, but have no idea why! Its probably something I've heard the old boys use and every now and then it slips in. Possibilities could be that I'm using a radar and giving you a heading but I know its not right - but who knows what goes on in the mind of an ATCO - we certainly don't!!!
trafficcontrol - I'll never explain why I'm using a heading so its definately not that. If a pilot doesn't understand why I'm using headings then he/she needs a visit to a centre last year.