RO never admittedly had that issue but im sure there were people that had done those alterations to game files.
I’m actually a fan of full invis skills but I’m aware of the fact that those tend to be the first things people create a 3rd party program or alter game files for.
I quickly remember some games that had this issue: Dofus online - Sram (assasin class) had a full invis skill which was countered by a lot of the top players by altering game files so they always knew where Sram is. This was confirmed and later on people were banned for it.
Heroes of the Storm - MOBA game, the stealth system in that game works so that you can actually see the cloaked hero if you look closely. However, some players have been using a hacked client since day 1 to see all heroes - including hidden ones on their minimap as icons. Therefore removing any advantage of ganking or stealth in general.
WoW has also been targeted by gamefile editing. Theres been numerous bans in the game for doing that to counter rogues. (Not confimed by me, just stuff I hear from people I know)
Elder Scrolls Online apparently has the same issue.
I didn’t bother start searching for more games with this issue, since im pretty sure you get the picture from this. And btw, even in tournaments people get caught with cheats (CS GO).
But yea, maybe im over thinking this, but in my experience stealth / invis mechanics have always been an easy target for people who want that little edge when playing. Probably due to the fact that it’s easy to get access to that information (where the invis hero is) from the packages and add a third party program to point it out on your screen.
Anyways, I just wanted to point out that when and if IMC decides to implement full invis skills, I hope they will also have a plan to deal with the cheaters, without doing shady sniffing around your computer like Blizzard has done and been sued for.