Its perfectly ok to cheat on this
Hell, I codebreaker'd and gameshark'd the hell outta this, D2 and Makai Kingdom back in the day, this shouldn't be any different even though its going to be the PSP version
Not being able to cheat is one of the reasons why I didn't get any of them for the PS3.
[Edited by DigitalIP, 2/4/2016 5:48:17 AM]
I've cheated on these games on whatever platform I've had them for. I like cheating in itself
Also, it is possible to cheat on ps3 without using custom stuff, albeit a tad more complicated than ps2 and older.
Currently pre-load of Disgaea is available on steam..... not many days left now. I'm hoping for an early release. :3