Maybe f4ke doesn't want to be able to choose the sigil stone. Maybe he still want to receive a random sigil stone, but he's pointing out this random choice is made too late (when you take the stone), so you can exploit it by saving then take/reload/take/reload/take/... until you take the sigil stone you want, thus breaking the random choice mechanics.
If a mod move the "random choice" to the moment you step in the Oblivion gate, a cheater would not be able to do take/reload/take/... because he would need to reload from before entering the Oblivion gate (and replay the whole realm) every time to get a different sigil stone.
Still, if he really like to cheat, I don't know what could prevent him from using console commands to circumvent the mod's limitation.