I didn't have this issue before 13.04 (had 12.10). I'm not sure it started to happen then, I don't reboot that often.
When I sudo reboot now from ssh or terminal the machine starts to reboot but halts with a screen saying:
Just sits there, nothing happens, I try different keys like 'Y' or 'N' or esc, space, return etc. nothing happens until I press ctrl+alt+delCode:Broadcast messagr from creepwood@Babel (/dev/pts/0) at 19:44 ... The system is going down for maintenance NOW! Skip stopping firewall: ufw (not enabled)
Then there's a screen with some [OK] and [FAIL] It's going by too quick to see what's failing. I tried the pause key, didn't help. I saw atleast two of them fails, and I think one of them was about not being able to stop all services before going down.
The weird part is, that if I do this in the gui, it works just fine. But since this is a server, I do most things by SSH.