online booking a vacation

Has anyone else experienced this?

When Ann and I were trying to book a flight to Mexico, we started looking around with expedia, travelocity, etc, using different search parameters, etc. After refreshing things, we wanted to go back to a deal we had seen earlier, so we entered those search terms... yet when the one we wanted came up, it had gone up in price about $100! We thought we were mistaken, so tried again. All the prices were slightly increased, and we were sure we were looking at the one from earlier. So I decided to move over from Ann's laptop to mine, and low and behold, the original fair came up! We didn't really stop to figure it out and we just booked it, but I have a sneaking suspicion that it was tracking my cookies and trying to get me to think... "Hey, its going up in price! I better act fast before it goes up anymore or gets sold out!" Devious to say the least.

Obviously I don't have much empirical evidence to support this, but I also wouldn't put it past them.