Its not cheating at all, but if a person decides to use an old game set up (as saved in the game editors) it is up to them.
If there opponent then looks back through games and sees what they think maybe the same game, they will win of course, BUT then what is either person getting out of it.
Is all the winner would get would obviously be a win, but using no tactics at all apart from looking at old games that there opponent had played. The loser would just have proved there is little point having Battleboats in the game editor now we have a Random placement option.