4Game

When you delete/move something around in stash, it doesn't send a request to the server(your stash is completely serverside, client is merely a display of it) right away. That's why when you spend a bit of time organizing but then BSG servers catch fire, you get an error and all of it gets rolled back in time.
Basically, your actions are actually applied to the database as a whole package of actions only when:

• You get out of the stash, either to main menu, flea, hideout, etc…
• You make too many actions(moved 100 items around), then the game sends the requests to prevent the request becoming too large in size.
• You pack/unload a mag, split&merge your ammo. There have been ammo dЦplication зxploits regarding ammo split/merge/loading, so maybe this was BSG's way of preventing it, i don't know exactly why these actions guarantee an instant request but it is how it is.

So as you can see, merely deleting something by accident is completely recoverable unless you do something else after that. Think of it as stepping on a hollywood landmine 😉
Closing the game normally also triggers a stash update request, so what you can do in these dire situations should you ever find yourself in one, is to PULL the ethernet(lan) cable, and force restart your PC.(you can just use task manager to force close the game but this is probably easier to understand for the non-techy crowd)

I see a "I deleted my kappa by accident", "I deleted my red keycard by accident" posts all the time so I thought I'd share.