Sure, here you have 2:
They also invented what i call the shadowcrap-dilemma:
1) To make a PoS Network "secure" you need to have nearly all wallets staking.
2) To make Ringsignatures "secure" you need all people to use them, always.
3) But you can't stake the tokens they use for anonymity, so being private and having a secured pos network can never be happen at the same time.
This is a typical example of getting fucked by your own greed.
1) Exchanger Wallets are sufficient.
The exchanger wallet model is extremely insecure because they can be hacked or abused by the exchange operator, or even just knocked offline with a DoS to create an attack window. It's the PoS version of centralized mining.
2) Monero doesn't. Mixing factor dependant.
Monero will have a minimum mix factor. Already there is a default mix of 3 in the wallet.