[bobbydigitales]

For a lot of types of games (e.g. social, creative, silly fun) it doesn't matter. For those where it does you have to run servers that you control and write server-authoritative code.

You have to assume clients are hacked whenever you're writing competitive games anyway, so there's not much difference there.

[a257]

Fair enough, I guess it doesn't really matter if someone hacks a drawing/building game. But people love competitive games.

I guess you can prevent most overt hacks through server-side validation. But still, that doesn't stop more sophisticated users from creating and using subtler hacks (such as aimbots).

[bobbydigitales]

Yep! Cheating and combating cheating is a never-ending arms race! You can use heuristics on the server to try and detect suspect behavior, but the issue is that the very best players can be very difficult to distinguish from cheaters. Even with client-side anti-cheat, you have to have the cheat before you can add the signature to have the client-side search for it and ban the player, so there are no simple solutions unfortunately. (Most of this coming from my previous life working on PC games :) )