Coding a whole new filter for a chest just so people can share items wouldn't be very practical, especially since it's so easy to give people items. You can also drop items at spawn, which essentially does the same thing as there are constantly people there. Typically if I see someone in chat asking for something, and I have it/have the money for it, I go ahead and buy it/give it to them, and there's probably a few others who do the same.
Either way, even if they managed to code a filter, there would be flaws and people would always find a way to flood it, or everything of value would be taken immediately. It wouldn't really benefit anyone except for a lucky few people who conveniently manage to grab stuff just by being at the right place at the right time- which, again, happens at spawn either way as people are always dropping items everywhere
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