this topic made me curious so i googled how do people generate tracking numbers for virtual goods.
there were a few ppl on bhw saying it can be done but did not explicitly say how. wouldn't hurt to seek them out and shoot a pm.
lots of variables here too. it's one thing to find/generate a tracking number that says package delivered within the proper time window. a much bigger thing for that package to match your customers city/address. may be as simple as sending an empty envelope to your buyer.
keep searching....how are they doing the Minecraft? likely they warmed the account up with some legit sales, then put on the Minecraft item. stuff like that, you can expect them to be banned within 30d usually. I've been reading lots of Esty threads lately. yeah you can sell goods against ToS like magic spells (remember that funny thread?) and you may make a couple grand. but eventually you will get banned. then you can reload and fight again with stealth's accounts. at this point it becomes a whole cat vs mouse thing. sure you will be net positive but you may be pulling your hair out dealing with multi accounts + suspensions.
best of luck getting the answers you seek. in my 1 minute google search i found a bhw thread guy claiming 400k+ monthly revenue selling cd keys (not etsy but digital goods related) and was open to questions.
i was going to link it to you but sadly he was banned for violating bhw rules.