So it's necessary to differentiate between dishonest activity at the level of the currency (e.g. inflation, interest), and "normal" dishonest activity which utilizes a currency in an honest manner, but to trade dishonest produce or services - e.g. buying drugs at market value. Bitcoin will be supposedly immune to the former type, but will greatly liberate the latter from the chains of state control. We might expect, for example, significant organized crime in a bitcoin world; but we're just coming back to a political argument here - anarchy Vs state, and there are other threads for that.
Interest is a market phenomenon, it is an application of time in economics, so I will have to disagree with your dishonest connotation to interest...
Basically if it is your opinion that the purchase or sale of drugs is "dishonest" then do not engage in such practices...
Take a less offensive example, tobacco is legal to own and grow privately in the US, but it is illegal to sell, trade or gift home grown tobacco.
If I were to sell tobacco I grew at my home, using bitcoin as a medium of exchange, am I using it dishonestly?
The use of bitcoin as a medium of exchange is illegal in the first place, why are you concerned that individuals will use it in order to trade contraband, when the medium of exchange itself holds the same legal status as a pound of marijuana?
Haha! That was *exactly* what I was going to post. 
You and I are true pals now.
You and I are true pals now.Nice to meet you then
