Re: Why removable disks mount in /media/<username>, not /media?
A quick search didn't yield an answer of the rationale, but it might be something to do with multiple users. For instance, it's possible to set up a network that has one server that runs all programs for all users. The thin clients are virtually just displays, keyboards and mice. You can even have it set up so that the users can plug in a USB flash drive on their thin client, and the programs running on the server can access the flash drives.
In order to make this easier or more practical, mounting these into /media/<username>/ would make more sense than just dumping the USB drives for 30 users into /media. Most people leave the default disk label for their flash drive, and I can see problems if two or more users plug in USB drives with the label "Kingston" or "Datatraveller" or something like that.
I try to treat the cause, not the symptom. I avoid the terminal in instructions, unless it's easier or necessary. My instructions will work within the Ubuntu system, instead of breaking or subverting it. Those are the three guarantees to the helpee.