Hi,
If there is no zone restriction it will allow all countries.
When you manage the zone in the HikaShop backend, you will find a "group" called "shipping zone".
It that group (or category) you can create your own zones (for the shipping). You can for example create a zone with all countries but without the USA and Canada, a "rest of the world" zone 
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.