Well an American on the shuttle with me from Seattle to Vancouver was being interviewed before me, just say I wasn't eavesdropping.
It started off with him being on disability in the US and not having worked since the year dot.
"How do you manage", asked the female immigration officer"
"Jesus Christ" he retorted.
It took all my self control to suppress a giggle, he wasn't doing himself any favours.
Just when I thought it couldn't get any worse for him the conversation took a steep downhill turn.
Turned out he had a criminal conviction for assault. I was astounded, almost felt sorry for him if he'd changed his ways. He was ordered to take his bags off the bus, the immigration lady said she'd decide later whether he would be allowed to continue his journey. Our driver whom I had offered to the grateful immigration official to bring in & sort out the fray (he thought I was the one in the stew
) said he hadn't a hope in hell in getting into Canada.
If you have a criminal record you definitely can't get into the US under the visa waiver scheme, I'd say it limits your chances of getting into any country but don't know if it makes it 100% impossible or if it varies from country to country???