In this case Letter of Guarantee should be a proof, that generated address regarded to chipmixer, nothing more needed (i'm talking about before deposit step).
That's fake security. You'll still need the same level of trust, and if you'd claim you received empty private keys, you still couldn't prove anything.
It's not fake security, it's just a protection from multiscam, in case i'll get scammed by chipmixer i can prove it to protect other ppl form using scam service, but current chipmixer site doesn't allow me to do that, they can scam money easy and just say that i deposit to wrong address covering it by "reputation" in this forum.
You didn't understand my proposal, there should be
2 letters for this type of mixer (private keys based), one
before deposit - one
after. First letter prove that address generated by chipmixer, second one - private keys.
You still didn't answer: how should i prove that address generated by chipmixer in case they'll silently change it after large deposit?
Let's imagine someone lost 10 BTC. This guy register on forum and asking chipmixer about it. Chipmixer answer some bullshit about phishing or wrong deposit address, doesn't matter really. Of course on this forum nobody will trust a some guy who lost some money and even can't prove it except some unknown transaction to some unknown wallet, but will trust chipmixer because of their signature campaign and tons of ppl trying to protect service and money they getting from campaign.
So, as i said,
chipmixer can scam anybody anytime and you'll not able to prove it, because you have nothing to prove except transaction hash. Enjoy 'trusted' service, lol.