Hardware the issues regarding buying or selling a vita + memory with DD

[Mira]

I'm wondering one thing...as the title says if someone were to offer a vita and by doing so it promotes the fact that it has a lot of DD in the memory,how are the two parties supposed to deal with sony account?
much more is if the DD in question are kexploits games? (i know that with kexploits you should always stay logout but if in the future hackers find some other way in?)