by the way, if you want to see this actually happening, its pretty easy. Sit on bittrex and wait for a big green line. After that comes up, there will be a big red line almost the same size. sometimes it will be broken in two.
After that, you can check bittrex's wallet. You'll see a few people cycling money in and out... theyre always sending steem in, and getting SBD back out a few mins later, then sending steem back in.
Also incidentally, astute observers will note that there have been a couple of OK sized recoveries (like 2 weekends ago we went from 135 to 150 or so).
This is because simultaneous buy pressure on SBD and Steem in the external marketplaces does not create the arbitrage opportunity. This increase came along with an increase in SBD value from 82 cents to like 95 cents.
Its basically like lifting up the teeter totter from both ends, rather than pivoting it.
The problem is, there is only a certain amount of room for this, because SBD isnt very variable, and wont often go above $1. (and in general terms tends to move against Steem, not with it)