While i have never had this issue happen to me, after reading through this id have to go with Kainzo on this, is the leaders of the town are given a second set of LWCs that only work for them (only if they hold the rank) they would be able protect the towns storage, and be able to add players as needed to individual chests like personal locked chests.
There are a few issuses that need looking at
*possible limit on number of chests
*how to assign them to town mayors for town use only
*preventing the above mentioned leaders from useing the towns lwcs fro personal use
there are probably a few i am not thinking of, but these are the big ones i think. A town set of lwcs would be easier to manage than a sub-region (or at least i think).
This would make it the mayors/leaders responsibility to look carefully at all the wish to give premissions to, it may not prevent all incidents it would cut down on them and these new players that join for the purpose of screwing with a town would not be able to do much.
Though i do agree that the punishment for these players should be harsh, swift and sevre.
On an off note, I am again impressed how we can civily discuss things like this as a community, even with so many different opinions.
I like your post but I disagree with part of it -- child regions specifically. Those are really easy to handle. All you need is a world edit wand and make a cuboid selection within your town's chunk's. You basically add plots as a sub-region and label it. plot1, plot2, plot3, gatenorth, gatesouth, etc. so, basically how it works is that players added to only those child regions can build/destroy in that child region, this would have a few major effects:
1) citizens build rights could easily be managed to only where they're supposed to build.
2) vaults for townships wouldn't need LWC's (but as a bonus, mayors could get MAYOR-ONLY lwc's for use for the town, as we did before)
3) citizens couldn't grief anything outside of the gates to get into a town, and their plot.
If everything was covered then they'd be fine. The whole town would be raidable, but as long as the citizens kept their doors locked, and things covered or lwc'd by a mayor then towns could be used for storage again... and not personal regions.
The issue is that towns used to get around 100-200 LWC's, which was more than enough back in the day. I'd also like to point out that maps were reset more often so people had less time to acquire massive amounts of items to build with.
If you think about storing a double chest of every block and item, that's quite a few double chests. Most people aren't going to LWC farmed goods, they're going to LWC one chest filled with each farmed good, and then save the rest for iron ores for transmuting, coal and coal blocks, redstone and redstone blocks, have cut down on their storage amount, iron and iron blocks, lapis and lapis blocks, i mean, all of this stuff has an item and block, and are used for different things.
At best, I hope we would get Mayor's get mayor-only LWC's that represent the size and type of town they're in charge of.
Hamlet's get 50 LWC's
Town's get 100 LWC's
City's get 150 LWC's
Capital's get 200 LWC's
Kingdom's get 200 LWC's
This means if you had a Kingdom and one of each town you'd have around 700 LWC's possible. That's enough to protect about 100 people's shit. That's about how many we have in our Kingdom currently, even with dwindling numbers. If we recruited a bunch Those numbers could triple but people don't stay active, so it would just be good township/kingdom management to maintain your LWC limitations. This would also give some incentive for Mayors to want to upgrade their towns and keep them well managed.