Disable instant reboot by crtl-cmd-power or bring up a confirmation or wait timer Being a newbie to Mac I found it very strange that Ctrl+Cmd ⌘+Power instantly kicks my computer to reboot without even printing a warning of any sort.
The problem is that sometimes I mix it up with Ctrl+Shift+Power which is for screen lock. Neither I use any of these very often hence few times I accidentally hit reboot instead of screen lock, luckily without any unsaved work to recover..

Is there a way to either disable a instant reboot key combination or, if that's not possible then force to bring it up some "Are you sure" message ?

It's quite strange that such a dangerous feat is so easily accessible without any confirmation or keypress for X seconds before initiation of reboot is something user would expect at least.
Those keys are hard wired to that power operation. Apple did this because otherwise there is no hard power switch on the computer. I suggest using a smart corner to lock your computer, so you don't accidentally mix it up with restart or shut down (Cmd+Alt+Ctrl+Shift+Power).