Ok. Here is the relevant output:

# grep dyle /etc/group | grep lp
lp:x:7:lp,dyle,jasa,janos,zala
lpadmin:x:106:root,dyle

So the user is listened in the groups.

And the syslog for a printing page reads:

Nov  2 07:22:48 semirhage kernel: [  624.792716] usb usb8: usb auto-resume
Nov  2 07:22:48 semirhage kernel: [  624.792722] usb usb8: wakeup_rh
Nov  2 07:22:48 semirhage kernel: [  624.824024] hub 8-0:1.0: hub_resume
Nov  2 07:22:48 semirhage kernel: [  624.824049] hub 8-0:1.0: state 7 ports 2 chg 0000 evt 0000
Nov  2 07:22:48 semirhage kernel: [  624.824249] usb usb5: usb auto-resume
Nov  2 07:22:48 semirhage kernel: [  624.824252] usb usb5: wakeup_rh
Nov  2 07:22:48 semirhage kernel: [  624.856012] hub 5-0:1.0: hub_resume
Nov  2 07:22:48 semirhage kernel: [  624.856031] hub 5-0:1.0: state 7 ports 2 chg 0000 evt 0000
Nov  2 07:22:48 semirhage kernel: [  624.856087] usb usb4: usb auto-resume
Nov  2 07:22:48 semirhage kernel: [  624.856090] usb usb4: wakeup_rh
Nov  2 07:22:48 semirhage kernel: [  624.888014] hub 4-0:1.0: hub_resume
Nov  2 07:22:48 semirhage kernel: [  624.888033] hub 4-0:1.0: state 7 ports 2 chg 0000 evt 0000
Nov  2 07:22:48 semirhage kernel: [  624.888181] usb usb1: usb auto-resume
Nov  2 07:22:48 semirhage kernel: [  624.888185] ehci_hcd 0000:00:1a.7: resume root hub
Nov  2 07:22:48 semirhage kernel: [  624.929013] hub 1-0:1.0: hub_resume
Nov  2 07:22:48 semirhage kernel: [  624.929036] hub 1-0:1.0: state 7 ports 6 chg 0000 evt 0000
Nov  2 07:22:48 semirhage kernel: [  624.933958] usblp 6-1:1.1: disconnect by usbfs
Nov  2 07:22:48 semirhage kernel: [  624.933978] drivers/usb/core/file.c: removing 0 minor
Nov  2 07:22:48 semirhage kernel: [  624.933983] PM: Removing info for No Bus:lp0
Nov  2 07:22:48 semirhage kernel: [  624.934058] usblp0: removed
Nov  2 07:22:48 semirhage HP_Deskjet_F2200: prnt/hpijs/hpcups.cpp 331: WARNING: color pen has low ink
Nov  2 07:22:48 semirhage HP_Deskjet_F2200: prnt/hpijs/hpcups.cpp 350: STATE: +marker-supply-low-warning
Nov  2 07:22:48 semirhage hal_lpadmin: Running hal_lpadmin
Nov  2 07:22:49 semirhage kernel: [  625.954043] usb usb8: suspend_rh (auto-stop)
Nov  2 07:22:49 semirhage kernel: [  625.954063] usb usb5: suspend_rh (auto-stop)
Nov  2 07:22:49 semirhage kernel: [  625.954082] usb usb4: suspend_rh (auto-stop)
Nov  2 07:22:49 semirhage hal_lpadmin: hal_lpadmin triggered by usblp kernel module
Nov  2 07:22:49 semirhage hal_lpadmin: Using device ID from HAL database entry
Nov  2 07:22:49 semirhage hal_lpadmin: remove
Nov  2 07:22:49 semirhage hal_lpadmin: Found configured printer: HP_Deskjet_F2200
Nov  2 07:22:49 semirhage hal_lpadmin: Disabled printer HP_Deskjet_F2200, as the corresponding device was unplugged or turned off
Nov  2 07:22:50 semirhage kernel: [  627.704038] hub 8-0:1.0: hub_suspend
Nov  2 07:22:50 semirhage kernel: [  627.704048] usb usb8: bus auto-suspend
Nov  2 07:22:50 semirhage kernel: [  627.704051] usb usb8: suspend_rh
Nov  2 07:22:50 semirhage kernel: [  627.704067] hub 5-0:1.0: hub_suspend
Nov  2 07:22:50 semirhage kernel: [  627.704071] usb usb5: bus auto-suspend
Nov  2 07:22:50 semirhage kernel: [  627.704073] usb usb5: suspend_rh
Nov  2 07:22:50 semirhage kernel: [  627.704087] hub 4-0:1.0: hub_suspend
Nov  2 07:22:50 semirhage kernel: [  627.704090] usb usb4: bus auto-suspend
Nov  2 07:22:50 semirhage kernel: [  627.704092] usb usb4: suspend_rh
Nov  2 07:22:50 semirhage kernel: [  627.704106] hub 1-0:1.0: hub_suspend
Nov  2 07:22:50 semirhage kernel: [  627.704110] usb usb1: bus auto-suspend
Nov  2 07:22:50 semirhage kernel: [  627.704112] ehci_hcd 0000:00:1a.7: suspend root hub

Why does hal_lpadmin disable my printer? The printer *is* pluged in and turned on. When go to the CUPS Web Interface, I manually "Resume Printer" and I can print ... o_O