Does a police officer have an obligation to caution a "suspect"?

In R. v. Smyth, [2006] O.J. No. 5527 at paras 81 Trafford J. observed that the right to silence pertains to a person who is a “suspect” objectively viewed and failure to advise as to the jeopardy he or she faces may lead to doubting the voluntariness of any statements: 81 Where a police officer is questioning a "suspect," there is an obligation, at common law, to caution him. The failure to advise a "suspect" of the right to silence, the potential jeopardy that he faces and the fact that any of his statements may be used as evidence at trial is a factor against voluntariness. See Boudreau v. R. (1949), 1949 CanLII 26 (SCC), 7 C.R. 427 (S.C.C.). Depending upon the other circumstances of the case, the failure to caution a "suspect" may lead to a reasonable doubt on the issue of voluntariness.