How is it bad for my country if I send my bitcoins to another one without telling them? The amount of money in the economy of my country will remain the same, so I don't see how it can be a lost.
It's not bad. You didn't impact the economy with the bitcoins because bitcoins are not exclusive to your country. If anything, you only slightly changed it when you bought it (I'm assuming) with your country's money. Otherwise, there's nothing you need to worry about.
Besides, you should concentrate on Bitcoins more if there's inflation or some nasty thing going on with your currency. It could prove to be a more stable currency than yours.