Do you know how long the Americans keep information?
When someone receives a pardon, his or her file is wiped clean immediately, meaning that the next time anyone looks, there is no trace. However, the Americans probably keep the information for longer, unless you are telling me that they consult the database regularly and that they receive information as quickly as Canadians do and so have up-to-date information. That would avoid situations where, for example, an American customs officer might think that someone lied because his file contains old records.
Are people's files kept sufficiently up to date to prevent old data from accumulating in the American system?