No it does not make sense at all. I send you 27 coins and soon thereafter you "mint" 27 new coins. It becomes pretty clear where my 27 coins went.
This won't always happen of course. What I said above is that if it happens a lot, then anonymity is compromised. If it happens rarely or not at all, then it isn't an issue.
What if you send me 27 coins, then I send myself 3 more Shadow, then I convert 21 coins back to SDC tomorrow and 9 more next Tuesday?
I think that what's more important is that the user is in control of how often that happens. Some will screw it up for sure. Future versions of the wallet can help with that.
That's just guessing it's not proof
True
it's circumstantial could not e used as evidence would not stand up in a court of law
Well that depends. Circumstantial evidence can and is used in court, as part of a case. One little clue like this probably doesn't prove a case by itself but it could still be a relevant piece of evidence. It can be used as surveilance to start or continue an investigation to gather more direct and more damning evidence. In countries that don't quite abide by the rule of law it might make you look guilty enough to for bad things to happen even without "proof." I'm pretty sure that isn't what you want either.
Also, who's talking about court necessarily though? I thought the idea was actually keep one's transactions private, for example from competitors, employees, employers, former business partners, customers, suppliers, political opponents, repressive regimes looking to track and/or cut off funding to dissidents, ex-spouses, stalkers, etc., not just (perhaps narrowly) evade prosecution. I have no idea though, perhaps that is not the goal of SDC. It is certainly the goal of other coins I won't mention here.
and is fixed by not being careless
Not entirely. If I send coins to you, I have no control of how careless you might be with the coins I just sent you. If you transact with them in a careless manner, that creates clues that may point back to me. It also contradicts the notion of "ease of use" if the onus is on the user to "be careful" all the time, or leave a trail.
More to the point, consider the case of blockchain analysis. The goal of which is to take little pieces of information and put them together to make inferences about what types of transactions are for what purpose. That's how bitcoin tracing actually works in practice. There is no direct label on most addresses/transactions that tell exactly what they are, but by treating the blockchain as big data you can process it and make inferences.
The goal of anonymous technologies like shadow (at least as far as I know) is to remove those clues and stop the surveilance. It's more effective if you aren't incorporating transparent addresses and traceable transactions at a high frequency.
But as I said if it isn't used too much and most transactions are Shadow->Shadow, then this is nothing to worry about. So I guess its just a question of seeing how it plays out in practice.
