If anything the price should go down. When people buy things with bitcoins they are effectively selling bitcoins transitively driving the price down. If you want the price go up there have to be incentives to buy stuff with bitcoins such as lower prices. For many people it is cheaper to use bitcoins because they bought-in early, but that would be equivalent of cashing out their position and exposing their identity to the merchant, which most of the early adopters either don't want to do or would have done already when it was more favorable.
Well, unlike most currencies or commodities bitcoin can be traded at volume for currencies outside of a monitored environment. This means using bitcoins in a trisection does not effect the trading price, and people could trade in 'dark pools' or face to face for amounts significantly above or below the current 'market value' while having no effect on the market price at all.
Even if it where tracked people buying things with bitcoin can just as easily drive the prices up as down. As with all transactions you must take into account the value of both sides of the transaction.
