Originally Posted by
moondog
Many countries require proof of onward (or return) travel as condition of entry. Often, a simple airline reservation printout is sufficient, but I prefer actually booking tickets that I can cancel with little or no penalty.
Generally this is true, however the check is usually when you are at the entry point. Some of the countries may also track your exit (and with everything going digital, this should not be difficult for them). If that is the case, then I wouldn't risk it.
That said, onward doesn't necessarily have to be on the same ticket. If you buy two one ways and can show that you have an onward ticket (eg, JFK -> LHR -> HEL) they generally won't give you too much trouble. It's when you show up with no ticket and definitely no explanation that can get you into that bad spot immigration staff have.