Yeah, going along with what Messiah said, the game, whenther pourposly or not, looks for very specific data when it wants to render, say, Cloud. However, it's strange then that we can replace each aspect of cloud (or any other character) with other 3d parts. We could essentially make him look like Tifa (just with short hair), so perhaps the game only keeps specific track of what files are in its libraries.. but encoding such protection doesnt make a lick of sense, as the game first came out on the playstation as was un-moddable enough as is.
Does ff7 look for battle.lgp to be a certain size, then? Again, i doubt it... creating protection would just be a waste of the programer's time.
Or maybe, just maybe, (with respect and appologies to alhexx) the programs we use to convert back to .p don't work the way they're intended to.. at least, not in a way ff7 will recognize.. *shrugs*