My first response to circumventing this system would be to promote use of a barter economy with a useful, easy to obtain and widely available consumable, such as CRU, and conduct trades in CRU% instead of credits.
Of course, people will still use credits for minor transactions, but the lure of tax avoidance should be sufficient to ensure that serious transactions move to the stable barter medium. It would function much as Path of Exile does.
CRU is well placed as a currency as it may be spent for a chance to generate items of true worth.
It's not even relevant to me whether other people take up this idea. If I'm alone in its support, I will purchase CRU with all my currency, becoming a CRU monopolist and being able to sell some off at my convenience for purchase, placed so that my wealth is never taxed.
If CRU is taxed instead it is easy to move to Basic Armour, which is infeasible to make NoDrop.
There's always going to be some easy-to-sell staple that I can stock up on to liberate when I need to purchase something, so that any liquid credits are immediately spent.