What is the basis for the Improvement District of B.C. to rely upon the principle upon which it relies on the principle of proprietary estoppel?

The principle upon which the Improvement District relies in support of this approach is succinctly stated in Stiles v. Tod Mountain Ltd. (1992) 64 B.C.L.R. (2d) (B.C.S.C.) 366, per Huddart, J. (as she then was): ... where a party expends money on the land of another under an expectation created or encouraged by the owner, or even where the landowner merely stands silent, the authorities establish that proprietary estoppel may found a cause of action, a revocable licence may be rendered irrevocable, or the party's interest may be found in a licence coupled with an equity, the circumstances may establish a contract between the parties, or equity may require that the fee simple be transferred. The equity is enforceable against a successor in title who takes with notice. (2) 18A