At the recent PUBG Invitational tournament held at IEM Katowice, OpTic Gaming's Ian "Bahawaka" Crowe was caught exploiting a glitch that allowed him to see through walls. Which, as per ESL rules is strictly forbidden. And so OpTic Gaming's $12,000 in prize money for coming in second, was stripped.
You can see the exploit as used below, even though it only seems to have happened for a second.
In his defense Bahawaka claims that he was only getting close to the wall to try and hear what was going on outside. But, rules are rules. And the glitch in question is quite specific in putting weapons away and stepping a certain way.