Coincidence. I think engine use Double for internal calculation some values. Sometimes it have same value as you search. Sometime - not.
If it be game usage for store data then it must be persistent. But it not true. Then, I think, it is only coincidence. You can add found Double to Saved list for watch how that values changes on game.
No. If you change game internal values it can crash. For example array have 16 elements. Index of array have values 6. You freeze it. But array changes to size 5. Your index now out of bounds. Program access to it and get invalid data. For example pointer. It try use it and get segmentation fault. It cause game crash.
No. I do not have time to investigate every game. Even for GG I do not have enough time. I work only on weekend for it.