This was actually a known idea for quite some time, see this post here.
I briefly discussed this issue too in my last witness update, and I am glad to see some more attention to this!

For the past few months I have operated my price feed at a discount related to the difference in SBD to USD (currently 10% discount). Of course, it doesn't matter much as I am a back up witness, so I hope the top19 will adjust as well.