Ha ha, that's probably a good idea. That said, it's also valid to treat it as a two day jam and approach things from that perspective.
The last jam I participated in was a 5 day jam, and I only decided on the third day that I was going to make something. By adjusting my scope to match what I could do in 3 days, I was still able to make something (like most jam games, it had plenty of rough edges but was definitely more than I'd have gotten done if I was still trying to make a 5 day game!)