Nothing in this Part affects:
(a) the right of a person to refuse to answer questions or to participate in an investigation except where required to do so by or under an Act; or
(b) any burden on the prosecution to prove the voluntariness of an admission or confession made by a person; or
(ba) any burden on the prosecution to prove that an admission or confession was made in such circumstances as to make it unlikely that the truth of the admission or confession was adversely affected; or
(c) the discretion of a court to exclude unfairly obtained evidence; or
(d) the discretion of a court to exclude illegally or improperly obtained evidence.