Which scam do you have on your mind? Can you elaborate that more please?
If we can agree to that the whole banking and finance industry is a big scam continue reading, if not please answer you don't agree and I can tell you way.
So if we look at the scams banks have been running we can take the FX scam that was almost unregulated market for many years. Giving the banks the chance to use retailers with insane marketing tools. The scam is easy you invest 1000 USD amount in a sell position in EUR/USD as currency paid. To simplify you start with 800 USD banks take 20% commission directly, on top of that you use leverage and are trading up to 500 times more. You now trading FX for 500 000 USD and 0,00002% movement will be 10 USD. Your position is closed if you reach 0 on your account wich is 0,0001% (approx). On top of that the bank will run a black book and a white book, betting against you. That means the bank take 0 risk and take 20% from you to bet against you and take no risk. Bank will earn 1000 USD on your trade and 99% of all FX traders loose there money.
The same tactics was used in the 2008 financial crisis, but this times it was with bad credits thats were repacked and sold as good credits, insured if they failed so the banks made insane amount of money on this.
The fund business is another example of frauds by banks were they charge 1-5% to run a fund and then they buy stocks, bonds from there own platform to a high price 1-5%. If the index of the fund is 20% the fund till perform 12-15% bank will make 5-8% on a index managed fund.
List goes on and on and on and on...
When it comes to bitcoin, banks makes alot of money on bitcoin because people want to buy, sell and exchange bitcoin. Take Wavecrest as an example a company who has a e-money licence on Gibraltar (they are not a bank, and regulation is much easier for them as well your money unsafe) They are also one of the biggest issuer of prepaid MasterCards for bitcoin wallets and bitcoin exchanges. So Wavecrest hold all there fund in Natwest Bank on Gibraltar and have 1 bank account and for there cardholders they show your balance.
So lets say you have 1 bitcoin and want to use this on a credit card to buy stuff.
Example with Wavecrest (Bitwalla is one of them who uses wavecrest for there cards)
1. You need to exchange bitcoin to USD high fee will be taken
2. Your money will appear in your online wallet in USD
3. Now you buy something with your wavecrest card
Fees wavecrest
Mearchant 0,2 USD + 0,5 to 1,5%
Fee client:
Transaction fee overall 10-15% (currency exchange, ATM fees, commission)
Of this fees bank will take there percentage, Master Card will take there percentage.
So banks will tap in to bitcoin and they have already thought about how to make the most amount of money and as well thought on how to contain and control bitcoin.
Wavecrest just so you know, runs a pyramide scam, what they do is that they block peoples card and just stop answering. They were filed for bankrupcy beacuse they froze 20 000 EUR from a cardholder.