This is like saying that open source software is more secure than closed source software because the code is public and auditable.
Sure it is auditable, but nobody is doing it. And then shellshock happens.
Yeah
Here's the money from the NiceHash hack two weeks ago (or "hack") getting moved out, in plain sight:
https://bitinfocharts.com/bitcoin/address/1EnJHhq8Jq8vDuZA5a...
You can kinda see what's happening (how it's being laundered) but you can't pin it on a given entity or idividual, unless they make a mistake.
You start off selling maybe 100 bitcoins which you've 'created', so the value of bitcoins on your exchange is 100 higher than in your 'wallet'. No-one can audit that and no one will notice because it's a tiny amount compared to the total volume. The more you do this, the more popular your exchange looks and the more you can repeat it and get away with it.
Eventually you be holding only a tiny fraction of the exchange book in actual bitcoin having cashed out 90% of it generating large amounts of money for yourself in the process.
If it ever looks like there's a run and you can't provide people with their bitcoin you claim "hack".
By the time you exit scam and claim "hack" the missing coins are gone but really they didn't exist so there's nothing to trace.
Wouldn't selling created bitcoin lower the price of bitcoin at your exchange? A lower price would attract USD and the exchange would leak BTC with people doing arbitrage.
Then if you claim a hack wouldn't you have to show that value moved to the hackers wallets and that value and the value you retain had to add up to the total value received in BTC? And if the "stolen" amount of BTC couldn't be shown to be in another wallet, wouldn't the fraud be discovered?
Currently this is very easy to do. Such trades are local to the exchange, so they don't register on the blockchain. If you execute them as "maker" (limit) orders, there aren't any fees either. So you can fake significant market activity for free.
Not necessarily. For example you can trade on GDAX (between ETH/BTC/LTC/USD) without hitting the blockchain. Once you "withdraw" your purchase and deposit it into "your" (because it's not really your wallet) wallet on Coinbase, then maybe.
Many of these "internal" exchange transactions are only reflected in their internal DB and not public blockchain.
An exchange who works like a normal eWallet, so your money are stored in their database only, is seriously suspicious. I understand there are people who will fall for these scams, but there are scammed people everywhere in the world.
Also, a serious bitcoin trader/buyer should always have the bulk of his Bitcoins on a personal wallet not on an exchange.
That's why exchanges are regulated. Step one of the regulation is getting the identity of all the owners. Step two is having servers and backups on regulated soils so you can seize everything at any time and reconstruct the ledgers.
Sorry, but this is so bloody annoying that I have to tell you:
"crypto" = cryptography (stuff like symmetric/asymmetric encryption, hashing, etc.)
"crypto currency" = useless shit like bitcoin
So I think you meant "exit scams" in the crypto currency space.