There is also an option in the settings that allows you to never target other players' pets. This is pretty useful - except in extremely rare cases when you need to be able to do so. For example, a dungeon run where your tank d/c'd and the group decides to continue using the Summoner's Titan-Egi to tank. (I've been in this boat many times, both as healer and as Summoner!) Just turn the option off for those rare cases.