And my last ignorant question, if you relock are there any complications running a custom ROM such as CM? Specifically, on reboot. Thanks.
When you unlock a device it wipes the entire device, so your data would not be at risk.
I do not know if it wipes it when it relocks it, but no it is not a complicated task. All it requires is one command.
"fastboot oem lock" to lock
and
"fastboot oem unlock" to unlock(wipes device).
Does that not help?
I have yet to see a single instance where Samsung actually improved android with their changes instead of just making it uglier, harder to use and less secure.
'People' shouldn't all run stock though, the beauty of Android as that people can run what they want (well, mostly, anyway...)