This worked perfectly! The player started up without a current playlist, and then when I rebooted the machine, it was basically a blank canvas. All the flash settings seemed to be reset. I had to reset my time zone and stuff, but more importantly, the visuals behave normally now.

I just searched the forums for "player -i", and the hits I found were mostly having to do with getting the player to start up with a blank playlist. I think it's important to emphasize that it's so much more than that. Since it's basically ignoring (and resetting) all flash settings, it's probably very useful for other situations as well.

Thanks so much, Hugo!