Well, if the onside kick isn't successful they're only hurting themselves by giving you great field position. Ditto if they go for two unnecesscarily and don't make it. They're costing themselves points. But there really should be fair-play sim settings for those who want a game that mimics real life. No onside kicks until the 4th quarter and only if you're losing, can't go for it on 4th down unless a team would realistically do so in real life in that situation, etc.