The same thing happens every year in Alaska when people get their Permanent Fund dividend checks (usually around $1k-2k per capita, varies a lot). It's advertised all over the place in the fall - spend your PFD here! New TV! New car!
For a large family (since each resident gets the dividend, even infants, as long as they physically spent enough time in the state the previous year), it can be a substantial amount of money - often enough to pay a few months rent, mortgage, utilities, property tax for the year, so many options... or, God forbid, invest!!
I'm sure that there are many people who do sensible things with this cash, but for so many it just evaporates like all "found money" does.
"Refund parties..." Now that's an idea the Mustachian community might actually get behind. See how far we can stretch our tiny piddly refunds! I would love it if every year, my refund check is just enough to buy a nice 6-pack of craft beer or something.