If it's your 1st notice you've got nothing to worry about, that's just a heads up don't do it too often. The system has built in leniency for life's unexpected emergencies and Riots stated that many times. But if it's happening enough to get you banned/restricted then it's an issue and you should fix those issues before playing again.
You shouldn't need to be compensated for it more than you already do and if you're asking for a free ride beyond what's already being given then you're out of luck because Riot's not going to do that. The bots only afk for a bit but the issue is you queued up and you left and if you keep on leaving that's an issue that Riot doesn't want it to become a habit.
If you think or know something will come up then play a custom bot game which is actually not much different than co-op vs ai other than you control who joins and anyone can leave at any time. If you queue up then ensure you're not going to be interrupted so that you don't affect anyone else. I've had friends have to leave for real life stuff so it does happen.
But again Riot's not going to change the rules for a small minority of players who either can't handle their time or can't plan better or shouldn't queue up if they have other responsibilities. They do however give you several get out of jail cards so to speak. It's up to you to use them wisely.