Less than $30 - I doubt you really have too much to worry about honestly. Now, if it was $300 or $3,000 - that might raise a few eyebrows.
Did you verify some of the information, maybe look at the IP address, etc? Send the customer an email - make sure the IP address is issued to the same company as the original order. This sometimes will help in catching any fraudulent orders
Fraud screening rarely necessitates banning an entire country before they order (or when they order). However, in the event that you get an order from a country which is "known" to have fraud or from which you have had problems it is your duty to pay extra attention. If you are manually reviewing all orders this is rarely an issue but if you have an automated system you may want to modify your fraud warning rules to give extra weight to certain countries -- again, not so you can simply cancel the orders but so you can take an extra look (does the ip match the country, are the addresses the same, what did they order, was their email address on a free service, how did they pay and what sort of shipping did they want).
I have been defrauded from the USA, the UK, Germany, Canada amongst other places. The place has nothing to do with fraud because it happens everywhere. However you should apply certain checks to all your orders to minimise your risk.
Well Romania is at least as famous. We have been kicked from ebay and paypal since some people did "nasty" things. That doesn't mean we are all frauds. And personally I'm a bit nervous when my own person is held to a low trust for others fault. So, I'd say to ship. Maybe ask for the money up front.
If the billing address is the USA and shipping is somewhere else, I'd be careful. If the billing address & shipping address are identical and the ip address matches the mailing address country/city.. You may also want to telephone them to verify.