A small number of places in ChernarusPlus 2.0 are intentionally locked or inaccessible at first. Getting in requires preparation, the right items, the right knowledge; sometimes all three at once.
Sealed doors in the hills, registers that only answer to their keys, chests that were placed with intent, and at least one site this website refuses to name: none of them are walk-in. None of them are pointless either.
The ChernarusPlus 2.0 briefing shows what we're willing to show, and the Lore tells you how it all got here. The rest is exploration, conversation and trial-and-error. Everything you can't reach today is reachable by someone, eventually. That someone could be you.
"A lock is a promise somebody made to themselves: I am coming back for this. This country is full of promises nobody kept."