Ok location number 1: The radio tower in golden rod city, reason: because it can make ur game freeze and you might wind up skipping parts of the main story which you NEED to complete or you wont get certain things like the nat dex, #1 place not to use the ww cheat: the very top.
location number 2: dragons den, reason: same as the last 1 but there r 2 things to know about it, places not to use the ww cheat: when ur leaving the cave after u take the test, and dont try to go to the room behind the main guy who gives the test. Effects: same as the first
and the 3rd and final location i noticed: dont try to walk through the boat house at either vemillion or olive city, it will freeze ur game.
thats all for now if you find any more locations PM me please. also here is my FC: 3226 8403 2830. I am only avaiable every OTHER weekend so pm me when you wanna battle but remember ONLY EVERY OTHER WEEKEND is when im on wi-fi