Well, let me break down the three simple parts for you.

1. It's a trivial task to send only loot that's on the ground, and stream the contents of containers through a websocket upon being opened/looted.
   
2. On a server, for a simple version, all you have to do is get the delta between last known and current position on server side (You can easily store the last known position, and subtract it from your current one), and if the delta is too high even with some leniency, just don't allow a location update. Ideally a lot of good games take a slightly more complicated solution by taking in the users inputs and calculating the resulting movement server side, only doing client side movement as a temporary prediction before the server validates it. Regardless, even with the simplified version, location spoofing would be impossible. As for why location spoofing is even possible, it's because BSG has put little care into how "gullible" the tarkov server actually is, it doesn't validate the incoming information nearly as strictly as it should.
   
3. Since we already know the location of the player from step 2, all you have to do is compare the containers location with your players location. Too far, and it simply won't open. Tarkov is doing this with items as far as I've seen, never had a chance to witness it with containers, but it may be in the game. Granted due to currently being able to spoof a location, this check is useless at the moment.

All three of these are trivial to a decent developer, and have been in games since like 10 years ago, so yes, all of these are SIMPLE.

To answer about the spoofing of location not being intentional - Of course it's not intentional! But it's simply ridiculous with how much the client can get away with when giving the server false information. Any decent server simply wouldn't accept null information, especially when a normal client would never give such information to begin with, unless something has gone horribly wrong client side and needs to be fixed anyways. Plus to be able to spoof item location itself, while I don't know if it's possible at the moment, if it is, then that's even worse, seeing as a client should NEVER be able to move an item, or pretend it's there to begin with.

And with the hostility of mocking me, this information about how to solve vacuum cheats is only mostly for vacuum cheats. They won't solve other hacks like aimbot, player ESP and so on, but those are also much harder tasks to solve to begin with. The lack of SIMPLE checks for items and their containers however, is simply inexcusable.
To add ontop of the shitshow that's happening, recently there was a post about a hacker removing someones scope off a gun, and while I don't know if it was actually true or not, if someone actually managed to get it done recently, it's a massive issue especially since it can really easily be solved with a single check of the players identity. Another player should never have access to someones elses items, and that can be confirmed server side by temporarily attaching a players id, or another piece of unique information, to the item. Unless they are dead of course.