There is a CYBER themed Cold North banner available for events at Helsinki Hacklab (used first time at CCCamp19). This design could be turned into a sticker too. The banner should cost less than 50 euros delivered, the design files are available in this wiki (File:ColdNorthBannerDesignFiles.zip). The font is OCR A Bold https://github.com/robertfoss/OCR-A-Bold
Whether or not we should bring (especially large) national flags, maybe a some sort of banner with a club logo, fancy art, or something like that might be a better alternative. We can probably show out our locality and background using other means. Prominent flags might be considered irritating by some and attract vandalism.