EXPLANATION
It can be very hard to track the exact amount of resources in your town, especially when it's big. And if you have nation and/or ally perms on in ur town, hundreds of people have access to alot of the chests in ur town.
EXAMPLE
When I was the mayor of my fort (Nishinohoshi), I had to call the mods on a multiple times a week basis to my town to check that the correct people took the supplies that are in chests (it was common for newbies to nick sets and xp as well as items suck as gunpowder,diamonds and steel). And half of the time it was the person who I allowed who took it and the other half it wasn't, but it still took up a large amount of the mods time.
CONCLUSION
If you implemented this, a mayor would be able to keep track of his items easier as well as prevent stealing and not waste a mods time.
REPLY TO THE ARGUMENTS YOU MIGHT SAY
Locking the chests:
I can't /lock the chests because many people may need access to them suddenly (for a siege), and I may not be able to come online and unlock the chests. It will also mean lots of people will need access to my locked chests which means they will also have access to chests of my personal items as well as areas with restricted access. Also most of the chests are nation resources (nation members can take them if they ask me and have a fair reason) meaning I'm OK with most people taking it, but sometimes they don't ask and take it for a dumb reason and I don't wanna remove everyone's access cause of them.
Pls consider it thanks for reading.