Just simply don't allow access to your account in the first place. If there is a password protection system on your items, it would also have password forgetting problem, Recovery option could be "bypassed" by someone somehow. adding password protection isn't a good idea.. there could be other ways around it. this will also drastically increase people sharing their accounts with others, assuming their items are protected. And could lead to more scamming / stats reset complaints. Also people will share accounts to allow other people to spar/pk/events for them freely. Which can affect the game in many ways. Certain rewards/items being too common vice versa.

Other way around your problem can be storing items on a separate account.. or just don't access at all.