Following is taken from your portal @ https://blindmixer.com/fees

WTF does this mean?

You'll take my Bitcoin, if I don't touch it for a year?

C. How do you make money?
Answer: We wipe the custodian every so often. This means that all the funds that are still present in the custodian at that moment in time, we claim for ourselves, and the signing keys will be regenerated. This has some significant advantages:
I. We can run our services at cost. II. We are disincentivized to exit-scam. III. Other users are disincentivized to exploit our software (and more likely to report it for a share of future profits), as there'll be less funds present than if we weren't to rollover given that over time there will be a set percentage of users who will forget about their wallet, not care, or are otherwise unable to access it.

In your mixing wallet, you can see exactly when the wipe is scheduled for your custodian (https://mixer.blindmixer.com/, once logged in head over to "FAQ"), and we also mention it above (see: Rollover Date)

You're right, though I think we can partly attribute it to people thinking of us being a "wallet" wallet, which is not really the case. Poor marketing from our side but it should become extremely clear that we're not at all a wallet in the traditional sense of the word, and more of an intermediary. say like a giftcard (provider). Those expire.. well sometimes at least  Undecided

Also it would become very attractive for us to exit-scam as it is just a given that there's funds that will be left by some % of users. Perhaps if we offer the community a share in this it might become more acceptable? (the rollover profits that is)

It's also great to have these kind of cut-off points so that when a breach happens, there's not years worth of deposits lost, but instead it is contained for some period. As once we're breached, an attacker could sign for any voucher, basically invalidating all outstanding ones.