$12 sounds pretty reasonable to me to ship anything anymore, especially international. Prices HAVE gone through the roof. Futhermore, most companies don't just figure the price of shipping, but also the price of packing - "handling". Anybody who has ever done a large volume shipping knows that the expense of packing materials can not be absorbed. Now, the question of whether or not charging you shipping/handling on a warranty item is up for debate, but I'm sure in your fine print that's what it says anyway.
So, yeah, a little bit unreasonable.
If they said "Fly a Kite! You broke it, not covered." Or "Send it in and let our team of expert warranty snuffers void your warranty on the basis of abuse". The list goes on, anybody who's warrantied anything nows the drill. That would be a different situation all together. I'll take "$12 shipping and we'll have it out right away" anyday.