I see it as a role play of sorts.
You log in and have stuff. Everything you have is fair game; why should there be a special block that makes your stuff not fair game? Just doesn't make sense to me.
You log off, it's as if you "wandered far enough away so you can't get killed", but if you didn't take your stuff with you, too bad for you. It's still fair game. Don't want someone to destroy your base and take your stuff? Stay logged in. Can't because you have a kid/job/life/whatever? Then maybe PvP isn't for you. Why should other players have to suffer? Just doesn't make sense to me.
If you have a lot of time invested into a PvP server then you already don't have to worry about this happening to you, so why bother catering to the casual players? <--- This is not an insult, it is a comparison of effort put in by people who are on a lot and people who are not.
...they don't have a lot of time invested into the server, so they shouldn't reap the rewards of having had a lot of time invested, i.e. block protection.
If you /really/ want to make it so that players can keep their stuff safe, then just increase the backpack size so they can log out with their stuff and be done with it.
LCB's are used as punishment far too often as it is, they don't need to be in a game that really IS "Survival of the fittest". Gotta disagree with ya on that one big R.
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AND AS ALWAYS, the most important thing is to find the right server for you.