HD3D This sounds very useful, yet very tricky. You better not forget who got warned for what, writing down notes about bad-behaving users is usually a good idea (the moderator notes extension should do the job)
In addition to your suggestion, strikes should decide the duration before a warning gets vanished. For example, 1 strike = 1 week, 2 strikes = 2 weeks, 3 strikes = 1 month and so on... maybe leave it optional for admins to set the duartions. But yeah, definitely agreeing with this 🙂