Why spend unnecessary resources? People trying to cheat will find ways that are very hard to prevent.
Which brings us to another question - besides hackers, who is interested in cheating these kinds of games? Probably people who want to impress their group of friends who also play the game. I smell a market opportunity here.
Then you're either out in public, and they can retroactively fix the bug, or you're trying to sell them privately, in which case you're not gonna have much impact anyway.
It's the same as with hacking in mmo games. No one cares until you start publicizing your hacks, in which case they can just install your hack, see what bug it's abusing, and fix that.
Isn't that how Candy Crush makes money now? You spend money to buy your way to new levels, through the use of special items and bonuses. Or are you targeting the subset of people who want to pay to cheat, but want it to be secret.
I'd say that most people wouldn't consider paying for more lives cheating. But that editing the communication between the game and the client is.
It would be like playing an arcade game. Putting in quarters for more lives isn't cheating. Creating a device that you can put in the quarter slot and pull out to reuse that triggers the game to think it's just got a quarter is.
Which brings us to another question - besides hackers, who is interested in cheating these kinds of games? Probably people who want to impress their group of friends who also play the game. I smell a market opportunity here.