When you travel, any border official can question you about your criminal record and deny access to their country. For example, if you have been convicted of impaired driving and are trying to drive into the USA, the USA Customs officers can deny you access to drive across the border.
When you apply for a job or clearances, an employer will see that you have a criminal record, by requesting a criminal record check.
Persons with a criminal record may encounter issues with employment. Many employers require a criminal record check, and will not hire someone with a criminal conviction. If you wish to work in a government agency, you may find that employment is denied or you may be required to obtain a criminal record suspension (pardon) before considered for work.
When dealing with family law or child custody issues, a judge can take into consideration the criminal record as evidence of the persons character. A criminal record could be considered evidence of bad character which may have an impact on who or under what terms child custody or visitation rights maybe granted.
In regards to educational institutions, such as medicine, security, child care and businesses involving money, (such as banking or accounting) having a criminal record may disqualify the student from attending or graduating.
Any person applying for Canadian citizenship will be denied citizenship if they have a criminal record and those persons who do not have permanent residency in Canada may be deported where they commit criminal acts in Canada.
If you are not a Canadian citizen you can be deported due to criminal acts.
If you are currently volunteering or considering volunteer work, most agencies now require a criminal record check. If you have a criminal record you will have to disclose and provide to the agency your criminal record to which the agency may disapprove your application.
In regards to adoptions, persons considering the adoption process must pass a vulnerable sector search which will result in a denial due to a criminal record.