Simply, "It doesn't work like that". Very similar to how you can't just "hack bitcoin and change your wallet value". At best you can use your web inspector to add zeroes to your balance.
Transactions in ledger-based accounting require a source and target account. In double-entry, all transaction legs have to sum to zero. "$10 on Paul; -$10 on Alice."
Your "current balance" may be cached, but it's never used. Most financial systems (which I suspect extends to banks, but I could be wrong) will enforce recalculation of at least the tip of the account's ledger whenever a transaction comes out of it. You don't just add/substract from a cached number.
Transactions in ledger-based accounting require a source and target account. In double-entry, all transaction legs have to sum to zero. "$10 on Paul; -$10 on Alice."
Your "current balance" may be cached, but it's never used. Most financial systems (which I suspect extends to banks, but I could be wrong) will enforce recalculation of at least the tip of the account's ledger whenever a transaction comes out of it. You don't just add/substract from a cached number.