Ok, so 1 day later got some results. Looks like game guardian actually works with buying a negative value and no ban, cause usually they would ban a few hrs later. However, you cannot gain any else (coins, etc) by the mod effect since there isn't something that is in a static location and changes value that you can catch&keep with game guardian like backpacks. The value will change it's value live in front of you when you edit the value, but jumps to a diff address if you completely exit the buying interface. If it doesn't change live then the value jumped to another address and you need to redo the search, but it will still let you buy but without the negative-ing effect. I don't know how many backpack space you can get away with, but I stopped at 1500-ish. You can also splurge on other gem related stuff like mounts and stuff, as long as you kill all your gems down to under 100 (I got mines down to 10) before you close the game. Looks like it's server checked at pretty much every value that is considered "very high" besides backpack space, but won't care if you're broke. Maybe it will actually last a week this time.