I might have added the wrong shortprefab names to the default config, I highly suggest you get the plugin debuginfo and find out the true shortprefab names for the objects you want excluded.
Enabling teams would allow members on the object owners team to be able to use that object.
"Also, I know that when mailboxes and dropboxes are used, once the item is placed in, only the owner can retrieve them." that is semi correct and not an issue. dropboxes and vending machines are two sided, It is done so people don't steal from behind them while still being able to use them, but Mailboxes don't work that way so i would not say their functionality are the same, because of that they are in the excludedentitys list.