A TRP is essentially a special permission given to a person who would otherwise be inadmissible to enter Canada. Although, in most cases it is recommended that people should apply for TRP in advance and get permission before hand. There are cases where people do not have the time to apply in advance as the trip may be sudden or due to an emergency. In this case you may be able to apply for a TRP at the border itself.
Your need to enter Canada should be compelling enough to overcome the risk (if any) you may pose to Canadian society.