well Coinmetro exchange which is an upcoming exchange planned doing same thing with their exchange, they will buy their tokens back when the price is going down and put it back to sale when their scarcity. The deal is cool to me but I don't know how they will implement it, until it is test and prove working, i am not investing.
Yeah but putting it back to sale just adds sell pressure again eventually down the road thus ruining the value added from the buying to begin with