I have been playing lately just to check out some other distros. I have a 32gb usb3.0 stick and am using the wonderful isobooter and some smaller distro iso images. Booted to a couple and played with them for a short time then rebooted to my main puppy. No issues with that however when I inserted the usb stick again, there was now a new partition for lubuntu. I found it odd that it would create a new partition with a simple boot without saying something.
I choose "Boot Lubuntu" from the menu and when it had booted it had an install link on the desktop so I didn't think it would have created anything else on the drive. It appears to contain a shortcut to ubuntu so what is this really? It says it is a 1.8gb partition. Did it just create a another partition to reserve space?