Correct, that would change the ref. But don't use a javascript redirect, use a meta refresh, because if the person doesn't have javascript enabled, they won't redirect.
To blank to referrer, you would use a double meta refresh.
DMR:
send traffic to domainname.com/red.htm
red.htm meta refreshes to domainname.com/red2.htm
red2.htm refreshes to the offer.
Then your ref will pass blank 99% of the time, but some browsers will still pass the real ref
To be 100% sure, use php to check that the ref is blank before it redirects to the destination.
I'm launching a service that does this and a bunch of other things automaticly. Its being beta tested right now, but it should launch by the end of this month.