Originally Posted by
MSPeconomist
Many visa application forms ask whether you've ever been convicted of a felony and the same is true for the entry forms you complete for immigration in other places. Some countries have been known to find USA criminal histories, such as Canada denying entry to those who have been convicted of DUIs.
Very few countries make the effort to effectively verify the visitor's criminal history information.
Canada is not the norm when it comes to how countries actually process/admit US citizens for visas/admissions. Canada uses way more US criminal history info than most other countries use when it comes to ordinary US passport users.