I've had one sale (out of not very many) marked as fraudulent on Creative Market.
Sadly, this is just a part of doing business on the internet. I'd be hesitant to fault Creative Market for this. I know @BinaryMoon, for example, dealt with fraudulent payments quite a bit when selling directly.
And I get with their reasoning behind delivering the file even if a payment may be suspicious. You can't justify crippling the experience for 99.8% (assuming that number is for real) of customers because the remaining 0.2% are bad apples.
If I recall correctly, that fraudulent payment I mentioned wasn't marked as such for days after the purchase was made. I assumed it was a chargeback or something. In that case, there's not much they can do. Credit card companies are very biased toward the consumer when it comes to disputes.
With that said, I don't even bother adding new themes to Creative Market because there's so little emphasis on WordPress themes. Looking at their homepage, there's not a single WordPress theme featured.
It seems like they're trying to compete more with GraphicRiver than they are ThemeForest. Which is fine, I'm sure it's working out well for them, but as a (WordPress theme) seller, I would still avoid Creative Market.
Not for the reasons you stated, but because the sales are so low it's not even worth the time it takes to upload a file.
P.S. Not your fault, but I edited your post to get rid of those OpenGraph box things because they were causing mixed content errors.