I agree fully with — on that one, there are no way for us to prevent that (to be fair, it is not even our job to secure those kind of things, as AFAIK we did not created the IAP system used by those apps), and it basically remains more as a "specificity of that market" that you have to take in account, and work with.
Sure it might seem " risky" ( what if everyone end up doing this ??!) or even unfair (All that work I putted on and I do not even have what I desirve), but as you can easily gather (for the majority at least), if the player do not want to pay for it, he will either pirate it or not use it at all, both I consider equaly as bad, and unfortunatelly, that is a part of the market you are targetting, the best you can do is "being fair" (so people will not uninstall or work around your app) and hope that the clients you are targetting are "honest" (not people that just wants everything for free, but you would not consider all your customers as potential stealers I am sure so that part should be okay), as everything you can try to do to stop them atm will be removed from the unofficial versions but will affect the legit ones (aka the "non-legits" users wont even see it, but the legits ones will suffer from it).