If you're not modifying the game code or memory space (which is what gamesharks/genies/whatever do), it's not cheating. All you do is operate at maximum efficiency within the rules set by the developers. If the devs forgot to clarify one of their "rules" (aka sloppy programming), that's their problem, not yours.

A peninsula of power that I often use in FF7 is the alarm thing in Junon. Triggering the alarm there as soon as you get there will turn the area hostile and you will run into enemies meant to be fought when one of those weapons attack the city, which is midways in disc 2.