Kinguin uses special software to detect fraud and I am fairly sure that a first purchase on it will almost always require 3Ds.
As for G2A, from what I can observe, they use multiple payment methods/gateways all with their respective anti-fraud measures.
None the less, gift card marketplaces are very aware of the potential of fraud on their platform, so I would assume it would be extremely difficult not to encounter a roadblock.
I myself am new to the carding space so if anyone would like to correct me, or add something, please do.