Does the doctrine of proprietary estoppel apply?

58. The Walls submit that in any event, the mailbox should be allowed to stay at its previous location. They say that the mailbox was previously in the disputed area for many years. I therefore considered whether the doctrine of proprietary estoppel could apply. As noted in Cowper‑Smith v. Morgan, 2017 SCC 61, proprietary estoppel may arise when a. a party represents that the claimant will have some right or benefit over property; b. the claimant relies on the expectation by doing something in reasonable reliance of the representations; and c. the claimant suffers a detriment because of this reasonable reliance, such that it would be unjust for the party responsible for the representation to go back on their word.