Hey guys I feel your pain and can hopefully offer a little help regarding these issues.
Speaking as an Author:
Protecting your digital assets is a big concern for everyone. There is no way to guarantee your code doesn’t end up elsewhere. If there was a way, “big companies” would have found it by now. Whether software is sold here, independently or elsewhere - the odds of dealing with such situations should be known. Everyone should also be aware that there isn’t a golden answer to insuring your code isn’t stolen, cracked, copied, distributed etc.
Unfortunately, this is an aspect of selling digital assets, anywhere.
However… this does not mean you should not combat the situation in full force.
You should actively seek out cases and deal with them appropriately using DMCA notices. Targeting hosting companies will usually have faster results - and may sometimes result in entire websites being downed. It is an ongoing battle to protect your assets, but the whole idea is to take them down as fast as they go up - minimizing availability of your assets.
In some cases this takes a LOT of notices - which means a LOT of time. I’ve opted to pay a 3rd party company to do just this. Within a month I saw a noticeable increase in sales across the board. Again, there are periods of time that some are available, but the wheels are already in motion for a takedown.
Placing a ton of barriers on your code is not the answer. I’ve read a lot of forum threads regarding this topic over the years, and while some very creative ideas have popped up - I’ve yet to see one that covers all bases. Encryption, ofuscation, verification checks, etc - should probably all just be considered speed-bumps on the road to getting at your source… and speed-bumps to maintaining quality code.
Speaking as a Reviewer:
The Envato Markets are based around community - and a place for everyone to learn, including buyers. Some buyers may be purchasing your item to see the source - which is exactly why all source files are required to be in readable format.
The item, and all advertised sub-modules and features, needs to be functional right out of the box without user intervention. Items aren’t permitted to ask the user for a purchase key or license code to unlock the item or part of it. License keys are still allowed to create buyer specific support systems and forums.
Hopefully this info helps.