I never had trouble with it so far, until today, while I was renovating my shop in spawn. I had to move my stuff lower because I'm installing lava in the floor, so I had to move all my storage chests + insides.
I blocked off the entrance, making it realistic impossible for anyone to enter the building.
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While /cprivating my forges, I was suddenly pushed aside, turning around, player sieve was standing behind me, looking around. I was telling him to get the fuck out, but he was way more busy checking my stuff, especially trying to open every chest I had.
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I was really lucky that I locked them before, which wouldn't have been necessary yet as like I said my space was fenced off. I had to tell him several times, and once he figured out there's nothing to take, he flew into the first store and then finally outside.
This should be a complaint about sieve, and the possibility for Donors to access an area that they are very well not supposed, or allowed to access.