ARAM swaps
Here's a recommendation. When you swap champions in ARAM with someone, if whoever requested to switch attempts to reroll or trade with someone else, let one who accepted the trade decide whether or not to allow reroll/trade. If he did not agree to further reroll/trade, he just gets his champion back. Sometimes people reroll traded champion to troll and sometimes they just assume whoever accept the trade prefer the new champion. Just a thought.