Alarming sound when attempting to ban champions who are currently prepicked in your team

Please, this is a major issue.

If you prepick for example Leblanc, your teammates should get a warning sound or a 2nd confirming if they attempt to ban her cause she's prepicked on your team.

This happened DOZENS of time already with Katarina now, she gets instantly banned from teammates even though i prepick her (i was on iPhone sorry blabla). Please don't leave this untouched. My friend plays Kha'Zix and rages to oblivion if his own teammates ban him too. I'm pretty sure I'm not alone on this.