Not taking at side ATM as to whether to enable decay or not but was thinking...
When a base decays to the point where the items inside the base are now accessible, I'm assuming it is still against the rules to loot those items (eg: the player may be coming back on and would rebuild).
Players should of course always lock their TCs, boxes, etc to avoid theft, but when the walls fall, anything inside the base becomes accessible. I expect an upturn in player item loss due to decay. For sure the rules will need to be updated to note exactly what the rules are around this to avoid issues.