When a company is about to release a new product it can have two effects on the left over stock. That stock will either sell more expensive if there is still high demand for only a small amount of stock or it will be marked down to clear stock.

Airline seats are no different. If there is 5 seats left they will go up in price but if there is only 5 seats sold and the rest of the flight is empty then the airline would be stupid to close the doors on an empty flight without squeezing some more money out.

9 times out of 10 your ticket price will go up significantly as the flight date approaches. Unless you are going to call the airline to pay the new higher fare I fail to see why you should get a refund in the rare instances that the fare goes down.