I can see two problems - the first being that I doubt many LL owners click sponsor links very much when reviewing
SO most wouldnt even know you were doing it.
Second though, a much different problem - would be that I believe you would see a decline in signups and clicks to your sponsor as ther are a lot of surfers that use settings that would allow a refresh - but other than that I cant see a big problem with it - of course there will be a few LL owners that will question its use as it could also be used "in other ways"