So i'm wondering as well - what if someone decides to frame Chipmixer by saying that they got hacked/chipmixer did an inside job when they really just sent the bitcoins to themselves? there would be no proof either way, but the guy can do this under multiple accounts and then people will say chipmixer is a scam.
There is nothing any site can do against this. You can say any exchange, casino or other site gave you a deposit-address and changed it right after you deposited.
That is not true. Bitmixer offers letter of guarantee. They show input and output addresses and signs them with their private key. Customer see it before they deposit. This is very nice feature and we would really like to have it, but we cannot. Their method is non-interactive and both inputs and outputs are known before deposit and if anything goes wrong, they can complain public. Output of ChipMixer is unpredictable - you can pick whatever chip sizes you want, you can bet, you can freeze them with vouchers. It offers better privacy, but downside is that we cannot offer letter of guarantee.
I was not familiar with the letter of guarantee method used by Bitmixer, but now that you have mentioned it, I wonder why it isn't possible with ChipMixer. Once the mixing amounts have been confirmed by the user, would it not be possible to sign a message containing the final chips being output in the mixing process, along with the input? The chip sizes may not be known prior by ChipMixer, but once they are chosen by the user wouldn't it be possible to include in a signed message?
I have not yet tried either of the mixers out myself, so please forgive me if I misunderstand the process involved in either of these.