For copyright violations, I generally stick to this schedule:
Initial warning(s)
Final warning or 1-3 day block (depending on behavior and previous warnings)
I much prefer to give final warnings than short initial blocks, as very short blocks often aren't that much more effective in getting someone's attention.
1 week block
1 month block
3 month block
Indefinite block
Users must be given a chance to read and understand warnings and change their behavior before further action is taken.
Blocks are a deterrent and a means to prevent disruptive behavior, not a method of punishment. I am always willing to consider an unblock request if you can show that you understand why you were blocked and what you will do to avoid the behavior in the future. Other administrators are welcome to undo one of my blocks without contacting me first if the reason for the block is clear and has been credibly addressed by the user in a public unblock request. A ping, email, or talk page message would be appreciated in that case.
I am willing to consider placing self-requested blocks. My thoughts on the matter are similar to those of Beeblebrox.
Mere suspicion, guesses, hunches, and "I think so" are not enough for me to speedily delete a file. If you aren't sure that it's a copyvio, and have some reasoning to back it up, open a DR instead. I may not be from Missouri, but you've still got to show me.