I think the 1 strike and you're out of this system is a bit much. I think a good way to introduce leeway for people with good reasons while discouraging people from just quitting would be to give someone one freebie every length of time, say 3 months. That way people who genuinely have to withdraw for good reasons can do so, but people who quit every event as soon as it becomes boring will still be stopped.
I don't see how this system could be described as "you're out". Not being able to join any PvP events for 4-8 weeks, is not the end of the world. And no "innocent" person will ever get that 12 week PvP ban.
Like I've said before, it's all about
time management. Most PvP events we organize are not something you need to quit your day job over. Usually when people quit because they "don't have time", it's not that they suddenly became the busiest person in the world, it's just that they
chose to spend that time doing something else. If we gave 1 million dollar cash prizes to winners, I can guarantee that nobody would ever quit.
Sure sometimes the reason for quitting can be a legitimate one, like getting hit by a bus. That is however
extremely rare. Most reasons for quitting are things that the person in question did, or should have, expected to happen. When we didn't have a warning system, people joined just in case they somehow managed to find the time to participate, then quit after after they didn't. With Parasites, players will think twice before joining an event. This will naturally mean slightly less participants, but it will also mean much less quitters.
The way I see it, when players sign up to these events, they make a
commitment to finish the event. If they choose not to finish the event, and do something else instead, they will have to pay the price for it. It's taking responsibility for their actions.